Coolant leak Help! Leaking on alternator and down back of transmission. (1 Viewer)

[JG2002]

Hey Everyone,
First time posting so quick intro....I have an 02 LC with 209k miles. No major modifications, just larger BFGs and had spacers in there but one broke so I just went back to stock. I do some work myself(heater Ts, radiator, AC drain reroute, thermostat housing reseal and O ring, undercoating) and like to think Im somewhat handy but cannot locate this one. I posted the thread below but did not have any responses as Im assuming I either posted it on old thread or did something wrong. Having a hard time finding the source of the coolant leak and have been at it for several weeks. Very slow leak and usually drips after the truck is off. I was thinking front coolant bypass under manifold or water pump but that was recently replaced with timing belt(20k ago). All the posts are so helpful but cannot find one on this topic that has a resolution. Any help would be great.


You can see the drip of coolant to the right of the alternator

This is where coolant is leaking onto and also towards the rear of the truck from the front cross member around transmission.

Coolant leak near alternator

Just brought this 1999 Land Cruiser home last night, went to change the oil today and noticed a steady leak right near the alternator. Circles in red is where the coolant is coming from. Any help identifying what needs to be replaced to fix the leak is appreciated!

forum.ih8mud.com

 

[3_puppies]

crossmember is the front differential
IIRC the bolt with the drip on it should have a sealant on the threads when installed,
was any work done recently? just reread the post, most likely whoever did the work didn't use a sealant on the threads of the bolt in question

 

[2001LC]

You'll need to follow leak up to top. Also check both side of engine and lower time belt cover weep hole.

Possible:

• Water pump,. Which leak, is general only found lower halve area of front of engine. Most often down BK 1 (Driver side in USA left hand drive), can be down both sides and from timing cover weep hole. Not a common leak, if pump replaced, unless done wrong. But new OEM do fail, ~ 1 in a 10,000.
• *** Water inlet O-ring to water by pass installed improperly*** FIPG seal to water pump improperly done. Coolant hose to, water inlet, water bypass or throttle body.
• Water bypass where bolted to head, it's gasket. One on each side.
• Head gasket. Not common unless engine over heated badly, warping head.
• Thermostat cap seal or lower radiator hose top end. Typically see in front of drive belt, not on tension bolt as you show.

Note: If overheating (building rapid high pressure) or a stuck radiator cap. You'll blow coolant at weakest point.

 

[JG2002]

crossmember is the front differential
IIRC the bolt with the drip on it should have a sealant on the threads when installed,
was any work done recently? just reread the post, most likely whoever did the work didn't use a sealant on the threads of the bolt in question

Yes, coolant all over the front diff. but also making its way down the oil pain and backwards.
I did have the alternator replaced and did seem to start around then.... so Im assuming that bolt with the coolant on it has to come off to replace alternator?

 

[JG2002]

You'll need to follow leak up to top. Also check both side of engine and lower time belt cover weep hole.

Possible:

• Water pump,. Which leak, is general only found lower halve area of front of engine. Most often down BK 1 (Driver side in USA left hand drive), can be down both sides and from timing cover weep hole. Not a common leak, if pump replaced, unless done wrong. But new OEM do fail, ~ 1 in a 10,000.
• *** Water inlet O-ring to water by pass installed improperly*** FIPG seal to water pump improperly done. Coolant hose to, water inlet, water bypass or throttle body.
• Water bypass where bolted to head, it's gasket. One on each side.
• Head gasket. Not common unless engine over heated badly, warping head.
• Thermostat cap seal or lower radiator hose top end. Typically see in front of drive belt, not on tension bolt as you show.

Note: If overheating (building rapid high pressure) or a stuck radiator cap. You'll blow coolant at weakest point.

So the leak is occurring only on the passenger side and have inspected the area and been underneath many times to make sure it is only the one side. I will check the timing cover weep hole(if I can find it)

I just replaced the water inlet O-ring that was visibly leaking(coolant crust around the circular part) and thought that was the source but still leaking after I resealed the O-ring and FIPG seal to water pump. I know there are some opinions on which FIPG to use but I used the black stuff(103) and lubed the O-ring with silicone(but I heard I was supposed to use soapy water after the fact) Hope that is ok. They seem to be ok now but will check that again. I was thinking it was possibly where the metal coolant line comes from the back into the front water bypass. That looks like it has an O-ring there but nothing on these forums have any info on that and when I look down into the V of the engine under manifold I do not see any liquid(dry or wet) just a bunch of debris which I have no idea how that s*** gets in there.

My other thought was your 3rd possibility and my question is do I need to remove manifold for the front water bypass gasket replacement. I was thinking about doing the gaskets to check out but if I have to remove manifold might as well do the starter, gaskets, and bypass o-ring if Im in there.

I hope its not the head gasket as i had the truck for over 10years(2nd owner) and never overheated. Just had the temp pop up once due to low coolant but figured that was air pocket when I changed radiator lasted for 5 seconds and came back down. It was also leaking coolant prior to that.

Thermostat cap seal and lower radiator hose seem good with no signs of leaking.

Radiator is brand new and do not think its the radiator cap and temp never moves when driving.

Your help and suggestions are greatly appreciated!!

 

[2001LC]

So the leak is occurring only on the passenger side and have inspected the area and been underneath many times to make sure it is only the one side. I will check the timing cover weep hole(if I can find it)

I just replaced the water inlet O-ring that was visibly leaking(coolant crust around the circular part) and thought that was the source but still leaking after I resealed the O-ring and FIPG seal to water pump. I know there are some opinions on which FIPG to use but I used the black stuff(103) and lubed the O-ring with silicone(but I heard I was supposed to use soapy water after the fact) Hope that is ok. They seem to be ok now but will check that again. I was thinking it was possibly where the metal coolant line comes from the back into the front water bypass. That looks like it has an O-ring there but nothing on these forums have any info on that and when I look down into the V of the engine under manifold I do not see any liquid(dry or wet) just a bunch of debris which I have no idea how that s*** gets in there.

My other thought was your 3rd possibility and my question is do I need to remove manifold for the front water bypass gasket replacement. I was thinking about doing the gaskets to check out but if I have to remove manifold might as well do the starter, gaskets, and bypass o-ring if Im in there.

I hope its not the head gasket as i had the truck for over 10years(2nd owner) and never overheated. Just had the temp pop up once due to low coolant but figured that was air pocket when I changed radiator lasted for 5 seconds and came back down. It was also leaking coolant prior to that.

Thermostat cap seal and lower radiator hose seem good with no signs of leaking.

Radiator is brand new and do not think its the radiator cap and temp never moves when driving.

Your help and suggestions are greatly appreciated!!

I'd focus on the water inlet. Look at all points 360 degrees around each seal point to water bypass and water pump. Very likely the O-ring is your leak. Very likely, due to pits its port in water bypass and or pits in groove for O-ring of water inlet
__________

If I understand correctly. You had leak at O-ring of water inlet, that had FIPG in/on it. You replaced O-ring using silicone grease, rather than soapy dish water. You used 103 FIPG on water inlet to water pump.

Your current leak is very like the water inlet to water bypass in O-ring port. Not because you use silicone to lube O-ring. East coast shop do that often. But water bypass female port, where O-ring seals. Is likely pitted, from having FIPG in it. The pits allow coolant to pass O-ring.

You should've used FIPG 1282B (coolant) or equivalent, not FIPG 103 (oil) at water inlet to water pump. But likely not your leak, provide applied correctly.

We must clean and polish out minor pits. Rule with any surface to be sealed, is: clean, clean, clean and polish. This is especial import for O-rings.

Assuming leak at O-ring. You'll need to pull water inlet again, to determine course of action. Which will likely be "patch" water bypass or replace it. If water inlet pitted groove, it will likely need replacing.

The debris under intake manifold in the valley. Is very likely a old nest.. Rodent, wasp, etc. I see mostly rodents nest!

Always check coolant level by looking under radiator cap, top to the cap. Do this just before sun-up. Which is coolest time of morning. Needs to be after 6- 8 hour cool down. Best is to be parked overnight with front end higher than rear, as air moves to high point. Parking this way results in radiator cap being high point. Make sure to top reservoir also, and it's hose goes straight down, don't let it curl up the side. It's hose and cap must be free of obstruction, so check.

When air in coolant system, it will not work properly. For one reservoir will not do it's job. To much air, and temp sensor is out of the coolant (level below sensor). We then get a false low engine coolant temp on dash gauge. When coolant in block, gets very hot. It will expand so much, it raises to level it submerges temp senor. Suddenly, we see very hot or even red line on gauge.

Radiator cap needs to be replace as should thermostat and it's O-ring, with new radiator. Thermostat must be installed jiggle valve up. Jiggle valve is how it bleeds air from the system. A sticking rad cap, will result in excessive pressure in system. Then it will leak and may blow radiator.

All bolt have a specific torque. Coolant bolts are a must, they be torque. Most are 13ft-lbf.

You can remove front water bypass, without removing intake manifold in 98-05. If you know the trick!

The beginning of this video will clue you, to why your may be leaking at O-ring port.

 

[JG2002]

I'd focus on the water inlet. Look at all points 360 degrees around each seal point to water bypass and water pump. Very likely the O-ring is your leak. Very likely, due to pits its port in water bypass and or pits in groove for O-ring of water inlet
__________

If I understand correctly. You had leak at O-ring of water inlet, that had FIPG in/on it. You replaced O-ring using silicone grease, rather than soapy dish water. You used 103 FIPG on water inlet to water pump.

Your current leak is very like the water inlet to water bypass in O-ring port. Not because you use silicone to lube O-ring. East coast shop do that often. But water bypass female port, where O-ring seals. Is likely pitted, from having FIPG in it. The pits allow coolant to pass O-ring.

You should've used FIPG 1282B (coolant) or equivalent, not FIPG 103 (oil) at water inlet to water pump. But likely not your leak, provide applied correctly.

We must clean and polish out minor pits. Rule with any surface to be sealed, is: clean, clean, clean and polish. This is especial import for O-rings.

Assuming leak at O-ring. You'll need to pull water inlet again, to determine course of action. Which will likely be "patch" water bypass or replace it. If water inlet pitted groove, it will likely need replacing.

The debris under intake manifold in the valley. Is very likely a old nest.. Rodent, wasp, etc. I see mostly rodents nest!

Always check coolant level by looking under radiator cap, top to the cap. Do this just before sun-up. Which is coolest time of morning. Needs to be after 6- 8 hour cool down. Best is to be parked overnight with front end higher than rear, as air moves to high point. Parking this way results in radiator cap being high point. Make sure to top reservoir also, and it's hose goes straight down, don't let it curl up the side. It's hose and cap must be free of obstruction, so check.

When air in coolant system, it will not work properly. For one reservoir will not do it's job. To much air, and temp sensor is out of the coolant (level below sensor). We then get a false low engine coolant temp on dash gauge. When coolant in block, gets very hot. It will expand so much, it raises to level it submerges temp senor. Suddenly, we see very hot or even red line on gauge.

Radiator cap needs to be replace as should thermostat and it's O-ring, with new radiator. Thermostat must be installed jiggle valve up. Jiggle valve is how it bleeds air from the system. A sticking rad cap, will result in excessive pressure in system. Then it will leak and may blow radiator.

All bolt have a specific torque. Coolant bolts are a must, they be torque. Most are 13ft-lbf.

You can remove front water bypass, without removing intake manifold in 98-05. If you know the trick!

The beginning of this video will clue you, to why your may be leaking at O-ring port.

So I went back in for another Quick Look around per your suggestion and also removed the intake tube to expose the entire inlet and you were right!
Was still seeping at the 8 o’clock position which was being blocked by intake.
So it looks like I have to go back it to redo the o-ring on the water inlet.

To answer your question I did not use fipg on o-ring just small amount of silicone. I used fipg(103) just on the rectangular part(water inlet to pump) of the housing. when I removed the water inlet originally there was a gasket and looked like small amount of black fipg in a groove around the water inlet side. I’m second owner and believe that was originally the way it was installed. In hindsight, Shouldn’t I use that technique as it seems the gasket protects the fipg from contacting coolant?
The circular stem of water inlet looked clean with minimal pitting but will post pics when I remove again. I did torque it down to 27ft/lb(rookie mistake) So note sure that caused the issue and leak

The coolant reservoir level has not budged since the coolant leak but when I checked the actual radiator level it was low. The radiator cap is brand new as I bought oem radiator and thermostat was replaced around 20k ago. Should I still replace thermostat and gasket?
Is the truck not pulling from reservoir because of air in system ? I’ll check to make sure the tube isn’t curled.
I also see spots of dried coolant near radiator cap…is that too much pressure in system.

Also what is the trick to change the front by pass without removing manifold?!? Suspense is killing me. lol

Thanks again for your attention to detail….ur knowledge has been so helpful!!
Here are some more pics of the recent leaks.

 

[2001LC]

So I went back in for another Quick Look around per your suggestion and also removed the intake tube to expose the entire inlet and you were right!
Was still seeping at the 8 o’clock position which was being blocked by intake.
So it looks like I have to go back it to redo the o-ring on the water inlet.

To answer your question I did not use fipg on o-ring just small amount of silicone. I used fipg(103) just on the rectangular part(water inlet to pump) of the housing. when I removed the water inlet originally there was a gasket and looked like small amount of black fipg in a groove around the water inlet side. I’m second owner and believe that was originally the way it was installed. In hindsight, Shouldn’t I use that technique as it seems the gasket protects the fipg from contacting coolant?
The circular stem of water inlet looked clean with minimal pitting but will post pics when I remove again. I did torque it down to 27ft/lb(rookie mistake) So note sure that caused the issue and leak

The coolant reservoir level has not budged since the coolant leak but when I checked the actual radiator level it was low. The radiator cap is brand new as I bought oem radiator and thermostat was replaced around 20k ago. Should I still replace thermostat and gasket?
Is the truck not pulling from reservoir because of air in system ? I’ll check to make sure the tube isn’t curled.
I also see spots of dried coolant near radiator cap…is that too much pressure in system.

Also what is the trick to change the front by pass without removing manifold?!? Suspense is killing me. lol

Thanks again for your attention to detail….ur knowledge has been so helpful!!
Here are some more pics of the recent leaks.

View attachment 3520491

View attachment 3520492

View attachment 3520493

View attachment 3520494

WOW, looks like this engine lived at bottom of ocean. Crusty!

Yes, coolant expansion (reservoir) tank will not work properly, with air in coolant system. Biggest mistake made by DIY, INDY & dealerships. Is not checking under the radiator cap, after cool day at coldest time of day. Which must be done after parked 6 to 8 hours, to fully cool down. Best, is to park with front end as high point. Since air moves to high point.

Thermostat does not need replacing, if newish OEM. But if inlet cap (14ft-lbf) removed to for any reason. Like to: R&R, check condition or make sure jiggle valve at top. It's gaskets (O-ring) needs replacing. No FIPG, soapy water or grease used. Just be careful, thermostat/gasket doesn't down slip out of place while installing.

No gasket used between water pump & water inlet. Only FIPG 1282B or equivalent. FIPG 103 is for oil, not coolant. FIPG 1282, must be applied to completely clean and dry surfaces. It's important to be totally ready, to install. From time we start applying FIPG to torque 13ft-lbf bolts We're given in 5 minutes.

To replace water bypass joint in 98-05, without removing intake manifold. Remove throttle body (13ft-lbf), so need it's gasket (new OEM).
The hardline of fuel rail passes under, intake manifold. It's held in place with 10mm bolt holding a hard line bracket. That bolt and bracket are in the way. Remove the bolt, and slide bracket to one side. This allows the clearance room needed, to lift water bypass off it's studs. The 4 nuts (2 on each side,13ft-lbf) on studs, holding down water bypass to heads. You'll need new water bypass gasket (2), where it seal to head.

Tip to hold each water bypass 12mm nut, in a 12mm 6 point 3/8" drive socket. Place a piece of electrical tape over business end of socket, pushing tape into socket with nut. Drape tails of tape over sides of socket, sticking to sides. This jams nut in socket. So nut will not drop out of socket, as you R&R.


I never like seeing these screw clamps. They're not constant pressure and cut into hose during expansion. I replace with new OEM hose and clamps.

 

[2001LC]

Pitting we see:

 

[3_puppies]

Pitting we see:
View attachment 3521531View attachment 3521541View attachment 3521539View attachment 3521540View attachment 3521535

WOW, that is some corrosion
improper coolant serving?

 

[2001LC]

WOW, that is some corrosion
improper coolant serving?

For sure.
Either form not flushing timely, allow leak to continue, adding other than distilled water, using FIPG either wrong type Or in case FIPG on O-ring or gasket. These trap coolant in pocket. mostly due to Ph of coolant changing, and eat metal and rubber as it ages. Water introduce minerals, resulting in deposit.

The same FIPG Band-Aid, I do on block. See in my video above. Can be used on other pits. Replace the pitted parts, is best. But not always practical, like on block or heads. Sometime we'll FIPG Band-Aid, a replaceable part. Either part not available, time or cost issue. So we do a temp patch. These temp patch done right, can last.

Trick: supper clean, scrap flush so only pits filled, let dry over night before assembling parts.

Head to water bypass gasket seal point.

The head had a few pits. Look close you'll see they're filled with FIPG

 

[2001LC]

Hoses with pits must be replaced. They can't be patched.

 

[2001LC]

FIPG used with O-ring makes pockets coolant gets trap in.

 

[2001LC]

Keep in mind. Coolant will get into even the tiny pits. So where it may be so same a pit, O-ring or rubber of gasket, may seal. That pit, will than only get worst. Eventually it will leak!

Many write-ups and pictures in a Master Link, in my signature box. See Coolant and some restore projects.

 

[JG2002]

WOW, looks like this engine lived at bottom of ocean. Crusty!

Yes, coolant expansion (reservoir) tank will not work properly, with air in coolant system. Biggest mistake made by DIY, INDY & dealerships. Is not checking under the radiator cap, after cool day at coldest time of day. Which must be done after parked 6 to 8 hours, to fully cool down. Best, is to park with front end as high point. Since air moves to high point.

Thermostat does not need replacing, if newish OEM. But if inlet cap (14ft-lbf) removed to for any reason. Like to: R&R, check condition or make sure jiggle valve at top. It's gaskets (O-ring) needs replacing. No FIPG, soapy water or grease used. Just be careful, thermostat/gasket doesn't down slip out of place while installing.

View attachment 3521497
No gasket used between water pump & water inlet. Only FIPG 1282B or equivalent. FIPG 103 is for oil, not coolant. FIPG 1282, must be applied to completely clean and dry surfaces. It's important to be totally ready, to install. From time we start applying FIPG to torque 13ft-lbf bolts We're given in 5 minutes.

View attachment 3521485
To replace water bypass joint in 98-05, without removing intake manifold. Remove throttle body (13ft-lbf), so need it's gasket (new OEM).
The hardline of fuel rail passes under, intake manifold. It's held in place with 10mm bolt holding a hard line bracket. That bolt and bracket are in the way. Remove the bolt, and slide bracket to one side. This allows the clearance room needed, to lift water bypass off it's studs. The 4 nuts (2 on each side,13ft-lbf) on studs, holding down water bypass to heads. You'll need new water bypass gasket (2), where it seal to head.

View attachment 3521520View attachment 3521521
Tip to hold each water bypass 12mm nut, in a 12mm 6 point 3/8" drive socket. Place a piece of electrical tape over business end of socket, pushing tape into socket with nut. Drape tails of tape over sides of socket, sticking to sides. This jams nut in socket. So nut will not drop out of socket, as you R&R.


I never like seeing these screw clamps. They're not constant pressure and cut into hose during expansion. I replace with new OEM hose and clamps.
View attachment 3521484

Thanks again for the super detailed post!

Yes.. crusty indeed. I live about 1/2 mile from besch on the east coast and in the winters they spray saline water all over roads which just eats at everything. I had to do a s*** ton of work underneath using rust converter and RP-342 to repel water and salt to keep it the way I want it. But I think just the salt air eats at the surface of most metals. U should see some other trucks….frames have holes in them. Especially the tundras and my 4Runner(prior to my LC) frame was totally shot. Some of the pics I see of 100 series I know aren’t from the NE. Lol

So I topped off the coolant as you recommend
And hope that clears out the air in the coolant system and reduces pressure.

I will be following your advice on all these items and will redo water inlet and tackling the front bypass. I am going to take some pics of the parts as I take apart and may patch if pitting is small but may just replace inlet housing and Front bypass. That damn FIPG is pricey but want it done right. I wonder how many shops don’t use that stuff. When I took my o ring off it was relatively clean. Nothing like pictures u showed.

As far as the hose u pointed out….i had to do that cause the damn clamp broke due to rust (go figure) and can’t find that damn clamp and hose part number anywhere online. If you know it please share.

 

[2001LC]

Dealerships parts counter, can give you parts numbers. Or look-up for yourself, using your VIN#, at www.partsouq.com

The 1282B, is only FIPG I use for coolant. Which is a larger tube, than most here will ever use up. But there are equivalents, that can be used. Aisin has one coolant rated FIPG, so do others that're rated for coolant. They come in smaller cheaper tubes.


Whereas I restore these 100 series. With such care, procedures and parts, they'll last the next 25 years. Sound like you'd need only be concern with next 3-5 years. So may be more of patch work and finding cheapest methods.

Be alert to rust hole near exhaust fumes. A very bad one is found at the rear 1/4 tips, very near tail pipe. Exhaust can enter the cabin and be deadly. I recently patch the worst I ever had to deal with ever, in a quarter tip. Which wasn't much of a hole, compared to rust-belt-rigs. I used POR-15 as resin for fiber glass. I've "wondered" if those, with rusty rigs. Could fill cavities, to block exhaust fumes. With great stuff window spray foam.

Above rust spot, when hit with high pressure washer, blew out.

Also worth a note: Replace mufflers or any part of exhaust system with holes. We've issue with holes, two of which are most common:
1) Exhaust getting into cabin.
2) Exhaust heat cooking wiring.

 

[JG2002]

Ok….so I had the coolant lines pressure tested and the mechanic says the leak is almost definitely coming from coolant pipe assembly going from back of engine(heater tees) to the water pump. He thinks it’s the gasket but possible rust on the pipe. The thermostat housing with o ring are no longer leaking so your advice was spot on as I needed to redo that. I’m thinking about having him remove the intake manifold to do the job but may try it myself. I know if I’m in there doing the starter and intake gaskets should be performed? How about front and rear by pass gaskets too?
The leak is much slower now since redoing the thermostat housing. Couple drops here and there so it’s not an urgent job. Do you think it’s a job for a newbie….any forums on this? Tried to look up but couldn’t find any. Here are some pics of the housing redo. Some pitting on the bypass I’m going to fipg soon but the housing seemed decent and no leaks after job was performed.

 

[2001LC]

You can use a borescope, to inspect the water cross over pipe. It fits into back of water pump. seal with and O-ring.

 

[JG2002]

You can use a borescope, to inspect the water cross over pipe. It fits into back of water pump. seal with and O-ring.
View attachment 3551368

I can see a small amount of coolant just below where pipe inserts into water pump. I just wanted to make sure it wasn’t water pump or something else before I removed intake manifold or other areas leaking. I can also see a rubber o ring where the pipe inserts into water pump that has seemed to slide down a bit. Tough to see here but this is right behind housing I’ll try to get a better pic Any thoughts on how tough that job is….once im in there is it a matter of pulling out pipe and replacing o ring?

 

[2001LC]

I see it. Not for sure coolant. Since I don't see Toyota pink or red crusty. But I see what looks like wet spot. Be nice to get a mirror or camera shot ,to confirm.

I trick I use. I attach my compressed air to reservoir hose. Pressurize the coolant system to ~15PSI. Provided level not low, coolant weeps or even blows out radiator leak. Same may work for this O-ring on cold engine.