is this coolant or oil?

[AtoyotA]

I've been losing a small amount of coolant (about 1/4 of overflow tank) every 3 or 4 months. Seems to only really be an issue in the cold months (I check level before starting engine), which makes me think I have normal koyorad leakage from the plastic hose connections - that is normal right?

when i went to inspect if one of my rad hoses was leaking today, i removed the belly pan and plastic skid plate and saw these wet areas.

my question is, can coolant gunk up like this or is this tell-tale signs of oil seepage from the oil pan? if it's not oil, would this mean i have water pump leakage?

pic #1: oil pan - top of pic goes toward rear of truck, bottom of pic goes toward engine

pic #2: tensioner

pic #3: front of oil pan; serpentine belt in righthand portion of pic

pic #4: i wiped the residue off the tensioner

pic #5: wipe streaks on tensioner

I will posts pics of what is definitely coolant in the comments.

 

[AtoyotA]

pic #6: coolant splatter on air intake and upper rad hose

pic #7: coolant streaks on rad fins

pic #8: left side view (when facing engine bay) of upper rad hose leaking coolant onto radiator; fan shroud on right side of pic

so for some reason, i'm losing coolant where the upper rad hose connects to the radiator and it's dripping into the rad fins and getting blown onto the front of the engine.

but this doesn't seem to explain the wet areas in the first 5 pics... right? the leak seems to only happen on cold days, when first starting the engine. it's especially bad if i let the engine warm up in the driveway before driving away.

 

[Trunk Monkey]

Your first pics are oil, coolant dries like in your other pics - pink crusties. I'd check your valve covers, they can leak and show up lower places on the engine. I'd also wipe off what's there and then see where it comes back. As for the coolant, looks like it's time for radiator replacement, top tank might be separating from the body of the rad.

 

[AtoyotA]

Your first pics are oil, coolant dries like in your other pics - pink crusties. I'd check your valve covers, they can leak and show up lower places on the engine. I'd also wipe off what's there and then see where it comes back. As for the coolant, looks like it's time for radiator replacement, top tank might be separating from the body of the rad.

I replaced both my valve covers recently (PS 2 years ago, DS 6 months ago) and have neurotically checked my work for leakage at the valve covers on a regular basis. they are dry as a bone! good to know on the radiator!

 

[Trunk Monkey]

I'd still wipe off what's there and see where it comes back. Next guess would be oil pan.

 

[AtoyotA]

I'd still wipe off what's there and see where it comes back. Next guess would be oil pan.

will do. could oil pan leakage splatter onto the tensioner like that? your theory on the valve covers makes more sense since the oil would be dripping from above, but I really think those are good. I will check again now bc you got me second guessing lol.

 

[AtoyotA]

valve covers are good.

pic #9: PS valve cover

pic #10: PS of engine

pic #11: DS of engine

what could be causing all this gunk??

 

[Rhetoric]

Classic Koyo rad failure! Mine failed in that exact spot.

You gotta clean all that oil then keep a close eye. It could be from a few spots…

 

[2001LC]

Oil on and around T-belt tensioner. Is most often form t-belt tensioner pulley assy bolt threads. The pulley bolt threads are required to be sealed. When not sealed, oil leaks pass the threads. Bolt capture hole in oil pump, opens to crankcase area.

Oil at T-belt lower cover weep hole, is likely from same pulley bolt thread. And or if crankshaft seal, was replaced it then may be weeping or leaking. Factory installed originals, don't normally leak.

A third point oil leak, is O-ring at top of oil pump. They weep, but rarely seen at weep hole. Unless bad weep/leak.

In ant case. I'd just clean and watch area, and oil level. Likely no need to deal with until next T-belt service. Since looks minor, it's not enough leak to be worrisome. Unless T-belt was done just recently, then that is a bit much.

Tensioner pulley bolt, without tensioner or it's pulley assy.

Oil pump oil O-ring

tensioner pulley bolt capture thread port, back of oil pump.

Crankshaft seal (brown) (aka oil pump front seal)

Oil around throttle body to intake gasket. Is from old PCV hose. Some may be due to reused t-body gasket, allowing some PCV oil to pass.

Coolant, likely just some spliage, fan blew onto engine and air pipe. Clean and check joint between plastic top and body of radiator (aluminum).

 

[AtoyotA]

Oil on and around T-belt tensioner. Is most often form t-belt tensioner pulley assy bolt threads. The pulley bolt threads are required to be sealed. When not sealed, oil leaks pass the threads. Bolt capture hole in oil pump, opens to crankcase area.

Oil at T-belt lower cover weep hole, is likely from same pulley bolt thread. And or if crankshaft seal, was replaced it then may be weeping or leaking. Factory installed originals, don't normally leak.

A third point oil leak, is O-ring at top of oil pump. They weep, but rarely seen at weep hole. Unless bad weep/leak.

In ant case. I'd just clean and watch area, and oil level. Likely no need to deal with until next T-belt service. Since looks minor, it's not enough leak to be worrisome. Unless T-belt was done just recently, then that is a bit much.

View attachment 3841265
Tensioner pulley bolt, without tensioner or it's pulley assy.
View attachment 3841266
Oil pump oil O-ring
View attachment 3841272
tensioner pulley bolt capture thread port, back of oil pump.
View attachment 3841271
Crankshaft seal (brown) (aka oil pump front seal)

View attachment 3841279
View attachment 3841267

View attachment 3841270

Oil around throttle body to intake gasket. Is from old PCV hose. Some may be due to reused t-body gasket, allowing some PCV oil to pass.

Coolant, likely just some spliage, fan blew onto engine and air pipe. Clean and check joint between plastic top and body of radiator (aluminum).

your knowledge is invaluable... I did the timing belt 2 years ago (30k miles) and i definitely didnt use any fipg on that step bolt. do you apply it like loctite in just one vertical line perpendicular to the threads or do you coat the threads all around? does that affect the torque spec when tightening?

 

[AtoyotA]

Classic Koyo rad failure! Mine failed in that exact spot.

You gotta clean all that oil then keep a close eye. It could be from a few spots…

did you replace yours immediately or just keep feeding it new coolant periodically?

 

[Rhetoric]

did you replace yours immediately or just keep feeding it new coolant periodically?

I ran it for a couple months like that and monitored the level. I replaced it in the spring before the warmer months rolled in here and never looked back. I did not want my truck to suffer the overheating fate of many 2UZs.

I regret putting that in my truck, but I was new to these vehicles and didn’t understand the quality of parts Toyota uses.

 

[2001LC]

your knowledge is invaluable... I did the timing belt 2 years ago (30k miles) and i definitely didnt use any fipg on that step bolt. do you apply it like loctite in just one vertical line perpendicular to the threads or do you coat the threads all around? does that affect the torque spec when tightening?

I put a thin coat of Toyota FIPG 103 (oil), all the way round threads about 1/2' wide (up from end). Missing first two or three threads

 

[AtoyotA]

I put a thin coat of Toyota FIPG 103 (oil), all the way round threads about 1' wide (up from end). Missing first two or three threads

do you use the same 25 ftlb torque while the fipg is wet? or go hand tight and let it dry before torquing it?

 

[nissanh]

You must reposition the coolant hose going towards the oil cooler on upper thermostat housing shown in the Pic-6. It is abot an inch out!

 

[2001LC]

your knowledge is invaluable... I did the timing belt 2 years ago (30k miles) and i definitely didnt use any fipg on that step bolt. do you apply it like loctite in just one vertical line perpendicular to the threads or do you coat the threads all around? does that affect the torque spec when tightening?

Did you also replace crankshaft seal?

do you use the same 25 ftlb torque while the fipg is wet? or go hand tight and let it dry before torquing it?

Yes, since Toyota calls for the sealant (lube) on threads of this bolt. Whether a sealant wet or dry, it's still considered a lubricant. Todate, I've not had any issue doing so or using FIPG 103. But in the countless 4.7L timing belts I've done. Only one or two have come time to do again. I would like to see many more, with me doing a second time.

Could 25ft-lbf be a typo.
Well, there are many typos in the 20 different FSM set, for the 98-07 FSM of 100 series. but all have same rec on this timing belt pulley tensioner bolt.
One potentially damaging one is; Vane pump 3 mounting bolts. Which show 53ft-lbf in one spot of just one manual (IIRC the 2005 FSM, in timing belt components diagram). Correct for Vane pump is 13ft-lbf.

Was it an oversight, not reduce torque, perhaps!

There is a bolt that, is the same in the 100 and 200 series. Which is the front caliper mounting bolts. 200 calls that bolt, non reusable. When threads (200 series only) of new bolt examined. We can see a sealant/locker. 100 series has a torque spec of 90ft-lbf, whereas the 200 series has it reduce for lubricate to 73ft-lbf. Same bolt on bigger caliper and heavier vehicle.

Why did Toyota reduce torque of 200 series mounting bolt. With it's dry threads locker, threads are lubed. Why did Toyota start using thread locker on the 200 series caliper bolt. Issue of 100 series caliper bolt walking off. Why didn't they put out a change on 100 series, to use locker IDK?

Interestingly:
The t-belt tensioner pulley bolt, has same seal & torque 25ft-lbf, in all FSM 98-07.
The T-belt Idler pulley bolt, doesn't show a sealant (except 1 yrs FSM). But use same 25Ft-lbf.
Both are same threads into same aluminium oil pump.
Toyota Torque specs, always seemed on the lite side. I've used the 25ft-lbf wet, for years. Not seen ant issues. I'm sure someone here, could do the math, on how much torque the aluminum oil pump capture thread can withstand. My guess would be, more tha twice torque recommended (50ft-lbf)

Also worth a note:
The FSM states Three Bond 1344 or equivalent. Which is a thread adhesive. Yet the real goal is to seal out oil.

Adhesives like Three bond 1344, are pressure activated.
FIPG 103 oil, is not actually consider an adhesive. But does act as one, somewhat. Which anyone thats has had to separate oil pan, using any Toyota FIPG seal, finds, it does glue the parts together.

I have thead lockers, Blue, Red and red hydraulic.
I also have All Toyota FIPG's used on 100 series.
I've just chosen to use FIPG 103 oil, in this case.

 

[AtoyotA]

You must reposition the coolant hose going towards the oil cooler on upper thermostat housing shown in the Pic-6. It is abot an inch out!

holy shidddd thank you!!! im surprised it's held on this long!

 

[AtoyotA]

Did you also replace crankshaft seal?


Yes, since Toyota calls for the sealant (lube) on threads of this bolt. Whether a sealant wet or dry, it's still considered a lubricant. Todate, I've not had any issue doing so or using FIPG 103. But in the countless 4.7L timing belts I've done. Only one or two have come time to do again. I would like to see many more, with me doing a second time.

Could 25ft-lbf be a typo.
Well, there are many typos in the 20 different FSM set, for the 98-07 FSM of 100 series. but all have same rec on this timing belt pulley tensioner bolt.
One potentially damaging one is; Vane pump 3 mounting bolts. Which show 53ft-lbf in one spot of just one manual (IIRC the 2005 FSM, in timing belt components diagram). Correct for Vane pump is 13ft-lbf.

Was it an oversight, not reduce torque, perhaps!

There is a bolt that, is the same in the 100 and 200 series. Which is the front caliper mounting bolts. 200 calls that bolt, non reusable. When threads (200 series only) of new bolt examined. We can see a sealant/locker. 100 series has a torque spec of 90ft-lbf, whereas the 200 series has it reduce for lubricate to 73ft-lbf. Same bolt on bigger caliper and heavier vehicle.

Why did Toyota reduce torque of 200 series mounting bolt. With it's dry threads locker, threads are lubed. Why did Toyota start using thread locker on the 200 series caliper bolt. Issue of 100 series caliper bolt walking off. Why didn't they put out a change on 100 series, to use locker IDK?

Interestingly:
The t-belt tensioner pulley bolt, has same seal & torque 25ft-lbf, in all FSM 98-07.
The T-belt Idler pulley bolt, doesn't show a sealant (except 1 yrs FSM). But use same 25Ft-lbf.
Both are same threads into same aluminium oil pump.
Toyota Torque specs, always seemed on the lite side. I've used the 25ft-lbf wet, for years. Not seen ant issues. I'm sure someone here, could do the math, on how much torque the aluminum oil pump capture thread can withstand. My guess would be, more tha twice torque recommended (50ft-lbf)

Also worth a note:
The FSM states Three Bond 1344 or equivalent. Which is a thread adhesive. Yet the real goal is to seal out oil.

Adhesives like Three bond 1344, are pressure activated.
FIPG 103 oil, is not actually consider an adhesive. But does act as one, somewhat. Which anyone thats has had to separate oil pan, using any Toyota FIPG seal, finds, it does glue the parts together.

I have thead lockers, Blue, Red and red hydraulic.
I also have All Toyota FIPG's used on 100 series.
I've just chosen to use FIPG 103 oil, in this case.

amazing info! i did not replace the crankshaft seal.

 

[AtoyotA]

You must reposition the coolant hose going towards the oil cooler on upper thermostat housing shown in the Pic-6. It is abot an inch out!

do i have the wrong hose here? the right end of the hose is fully seated. there is metal inserted into the hose, past the left clamp, though, so that is reassuring.

 

[rexington14]

do i have the wrong hose here? the right end of the hose is fully seated. there is metal inserted into the hose, past the left clamp, though, so that is reassuring.

View attachment 3841551

It's fine. I replaced this hose with OEM (along with most of the other water hoses) a couple years ago when I did my radiator.

Here's what that area looks like with the hose removed:

And after replacing with the brand new Toyota OEM hose for this position, along with clamps: