Blown head gasket? Best options?

[nissanh]

I think your radiator is clogged. The way you went to burp the system is correct.

When I did my T-belt job, I had the cabin heater setting at 85 (both front and rear with fans on) and with radiator cap open I filled coolant half-way on top tank. Then started the engine and kept it at idle. When it started warming up, noticed coolant level went down. I then added more, again to 1/2 level (repeated as needed). Within about 20 minutes all went well. Got hot cabin and no more bubbles.

The sporadic bubbles you observe is normal during burping.

 

[beachcruiser]

System is self burping:

Fill radiator to top and fill reservoir. Run engine until hot. Allow to cool down over night.
Repeat only filling reservoir 1/4 full or less this time.
Repeat only filling reservoir to lower line (cold line) this time.
Repeat until levels hold. This usually take two or three cool down cycles.
Cabin heat should blow hot once system is full of coolant and air has been purged (burped). If system will not hold coolant you'll not get cabin heat.

Note: Full reservoir is at top line (hot line). Hot means normal operating temp.


Does oil look normal?

Thanks again...All the input is greatly appreciated. I would say this last round she lost close to 4-5 cups of coolant down into the catch basin under the truck, so I may not be able to hold adequate coolant to get heat at this point but I'll add some in the AM when I can also cleanly see whether evening temps caused vapor/steam at exhaust or if it was coolant burning off.

When I shut the truck off, I could clearly hear coolant boiling and top radiator hose has very hot/hard to touch. Lower rad hose and hose into tstat housing was not warm. Same for hoses into and out of firewall to heater. Hot in and cool out.

Oil appears dark translucent brown and is typical consistency. No froth/sludge that I'm seeing.

 

[2001LC]

With leak like that you'll not get heat. You many not be able to see coolant move properly through radiator if you can't get level high enough either. Or detriment if bubble from air in system or compressed combustion gasses.

A leak so bad it's losing 4 or 5 cups so quickly is bad. If this is water pump you'll see coming from front weep hole. It will loose coolant until level below leak. Use mirror or pull skid plate to see. If water pump, they don't just starter dumping all at once. It starts as slow seepage and grows as seal of/and bushing and shaft fail.

Assume the leak was there before you replaced T-stat, so we can rule out you just now started it during install. This would lead me to believe you've overheated the engine over the summer and fall.

Your radiator would have been low when mechanic tested for hydrocarbons, if leak was bad at that time. So it's not likely he fudged test with coolant in test fluid.

Try a balloon stretched over radiator neck while cranking or running engine cold. If balloon fills compression test is next to confirm, and to determine which head.

 

[beachcruiser]

With leak like that you'll not get heat. You many not be able to see coolant move properly through radiator if you can't get level high enough either. Or detriment if bubble from air in system or compressed combustion gasses.

A leak so bad it's losing 4 or 5 cups so quickly is bad. If this is water pump you'll see coming from front weep hole. It will loose coolant until level below leak. Use mirror or pull skid plate to see. If water pump, they don't just starter dumping all at once. It starts as slow seepage and grows as seal of/and bushing and shaft fail.

Assume the leak was there before you replaced T-stat, so we can rule out you just now started it during install. This would lead me to believe you've overheated the engine over the summer and fall.

Your radiator would have been low when machine tested for hydrocarbons, if leak was bad at that time. So it's not likely he fudged test with coolant in test fluid.

Try a balloon stretched over radiator neck while cranking or running engine cold. If balloon fills compression test is next to confirm, and to determine which head.

I'm guessing the combustion gases would create enough pressure to inflate balloon, as opposed to air from the burping of air in system?

I definitely didn't observe fluid loss recently, and I was all up under there during my recent rebuild of front diff and installing a new CV axle, so it's perplexing.
Once the Heater T blew during the initial "event" this past Friday, I had not seen it filled again with fluid, so I was a little shocked/dismayed by the volume of coolant raining down under the engine tonight after I topped it off.
I'll sort out where it's coming from during daylight tomorrow and let you all know.

Thanks again.

 

[flintknapper]

4-5 cups of coolant loss is a lot.

Regardless what else you find (clogged radiator/other) you will need to find and address the source of that leak. If from the front of the engine I'd look two places.

1. The weep hole for the water pump (found at the bottom center 'front' of the engine).
2. The coolant hose that goes to your Oil Filter Housing.

 

[ponytl]

I don't think it's the head gasket with what you have said... if you run it with the cap off and squeeze the radiator hose with your hand you can help it purge the air... it's time to replace the water pump and TB and hope that cures your ills... it really isn't a bad job with all the info and instructions posted here.. I get the kits off ebay for like $100 and they have always included name brand parts...

 

[2001LC]

I'm guessing the combustion gases would create enough pressure to inflate balloon, as opposed to air from the burping of air in system?

I definitely didn't observe fluid loss recently, and I was all up under there during my recent rebuild of front diff and installing a new CV axle, so it's perplexing.
Once the Heater T blew during the initial "event" this past Friday, I had not seen it filled again with fluid, so I was a little shocked/dismayed by the volume of coolant raining down under the engine tonight after I topped it off.
I'll sort out where it's coming from during daylight tomorrow and let you all know.

Thanks again.

Air burping happens when hot expanded coolant pushes out air through cap. As it cools contracting in volume it draws in coolant from reservoir. To burp the system needs to be sealed, have a good radiator cap and coolant topped off in radiator & some in reservoir.

Yes, the idea behind balloon is so you can see if it expands on each crank when cold. Normally you just make sure coolant system full and watch at neck of radiator for surge of bubbles. With such a bad leak you may not get system full, so I suggested balloon as visual aid. If you let engine run until warmed up then expansion of coolant would expand balloon, giving false reading for this test.

Possible you got lucky and have not been overheating long term. Possible the T's leaked some for awhile then blew on first overheat. Then not burping the system properly, it may have seemed T-stat bad. Then while replacing T-stat you didn't get sealed properly and that's your 4 cup leak. Test you old T-stat in boiling water just for "grins" if you like.

If t-stat housing leaks, you can stop it and get system properly burped. Then watch full coolant system for bubbles of combustion gasses.

Lets keep our finger crossed!

But I am concerned you mechanic knows his stuff. I'm concerned you've been driving for sometime with coolant system low. If low enough you temp gauge would not show true temp of engine. This is number one killer of the 2UZ-fe 4.7 engine. Running water pump dry of lubricant (low coolant) can also damage it over time.

Prolonged overheating blows head gaskets. Replacing head gaskets and have head(s) machined is a labor intensive job. labor cost is why many elect to just replace engine.

 

[beachcruiser]

4-5 cups of coolant loss is a lot.

Regardless what else you find (clogged radiator/other) you will need to find and address the source of that leak. If from the front of the engine I'd look two places.

1. The weep hole for the water pump (found at the bottom center 'front' of the engine).
2. The coolant hose that goes to your Oil Filter Housing.

During daylight it's obvious the smoking isn't significant at this point. Looks more like vapor.
The leak is def coming from what appears to be the rear of the water pump... can't see the source BUT it's dripping down directly onto the plate the oil filter mounts to. It's a steady drip under idle and I'm starting to wonder if we may be looking at two things: water pump and a potentially clogged or partially clogged radiator?

 

[2001LC]

During daylight it's obvious the smoking isn't significant at this point. Looks more like vapor.
The leak is def coming from what appears to be the rear of the water pump... can't see the source BUT it's dripping down directly onto the plate the oil filter mounts to. It's a steady drip under idle and I'm starting to wonder if we may be looking at two things: water pump and a potentially clogged or partially clogged radiator?

Water pump leak is almost always from shaft. It's seen from weep hole. Red arrow is weep hole, yellow is lower part of harmonic balance (large pulley on crank) & drive belt. This is with skid plate off, looking up from under front.

If you're seeing coolant here near VIN #, it's likely you did not get good seal when you did the T-stat, so you'll need to redo.

For grins:

 

[2001LC]

I've gone back and read the OP. I see you stated the temp gauge red lined and wife shut down. This is a very good sign you've not been overheating over the long term. It's very likely coolant system just had air in it (not burped fully) after H-Tee fixed. This would keep coolant from heater core, so no cabin heat.

So lets hope your mechanic did test wrong.

Fix the leak and burp the system.

 

[beachcruiser]

Air burping happens when hot expanded coolant pushes out air through cap. As it cools contracting in volume it draws in coolant from reservoir. To burp the system needs to be sealed, have a good radiator cap and coolant topped off in radiator & some in reservoir.

Yes, the idea behind balloon is so you can see if it expands on each crank when cold. Normally you just make sure coolant system full and watch at neck of radiator for surge of bubbles. With such a bad leak you may not get system full, so I suggested balloon as visual aid. If you let engine run until warmed up then expansion of coolant would expand balloon, giving false reading for this test.

Possible you got lucky and have not been overheating long term. Possible the T's leaked some for awhile then blew on first overheat. Then not burping the system properly, it may have seemed T-stat bad. Then while replacing T-stat you didn't get sealed properly and that's your 4 cup leak. Test you old T-stat in boiling water just for "grins" if you like.

If t-stat housing leaks, you can stop it and get system properly burped. Then watch full coolant system for bubbles of combustion gasses.

Lets keep our finger crossed!

But I am concerned you mechanic knows his stuff. I'm concerned you've been driving for sometime with coolant system low. If low enough you temp gauge would not show true temp of engine. This is number one killer of the 2UZ-fe 4.7 engine. Running water pump dry of lubricant (low coolant) can also damage it over time.

Prolonged overheating blows head gaskets. Replacing head gaskets and have head(s) machined is a labor intensive job. labor cost is why many elect to just replace engine.

From underneath, tstat housing isn't leaking, but steady drip is

I've gone back and read the OP. I see you stated the temp gauge red lined and wife shut down. This is a very good sign you've not been overheating over the long term. It's very likely coolant system just had air in it (not burped fully) after H-Tee fixed. This would keep coolant from heater core, so no cabin heat.

So lets hope your mechanic did test wrong.

Fix the leak and burp the system.

I'm hoping for an incorrect test too because after finding leak emanating from what looked like the base of the harmonic balancer, I decided water pump was the project of the day, and also after not being to empirically determine IF I was getting combustion air into coolant via the balloon test... seemed like it was just burping.

So long and short, after fighting the crankshaft nut, and finally getting front end stripped down, I freed up the water pump.
Pulley on pump spun freely. Impeller spun freely BUT they spun independently. They were no longer connected. Impeller was not turning with pulley. Just freewheeling which also makes me assume it was sitting stationary in the housing as the belt whirred outside.

I'm cautiously optimistic, and am reassembling now, and am aware this water pump and timing belt install may not solve the issue BUT can be swapped into the donor engine I'll snatch up if it turns out the HG was compromised. Hell, I'll have some practice and much like my first set of birfs on an 80 I used to own, it'll go much faster the second time. I really do appreciate all the help. I'll keep you posted.

 

[flintknapper]

If the pu

From underneath, tstat housing isn't leaking, but steady drip is


I'm hoping for an incorrect test too because after finding leak emanating from what looked like the base of the harmonic balancer, I decided water pump was the project of the day, and also after not being to empirically determine IF I was getting combustion air into coolant via the balloon test... seemed like it was just burping.

So long and short, after fighting the crankshaft nut, and finally getting front end stripped down, I freed up the water pump.
Pulley on pump spun freely. Impeller spun freely BUT they spun independently. They were no longer connected. Impeller was not turning with pulley. Just freewheeling which also makes me assume it was sitting stationary in the housing as the belt whirred outside.

I'm cautiously optimistic, and am reassembling now, and am aware this water pump and timing belt install may not solve the issue BUT can be swapped into the donor engine I'll snatch up if it turns out the HG was compromised. Hell, I'll have some practice and much like my first set of birfs on an 80 I used to own, it'll go much faster the second time. I really do appreciate all the help. I'll keep you posted.

If the pulley and impeller are spinning independent of one another then you've found your problem. Never seen that before, but if that is what has happened to yours, then for certain you've found the problem (or at least one).

In the future...to check Water Pump output you can remove the thermostat and disconnect any small heater hose, crank the engine and if you DON'T get a geyser from that hose then your water pump isn't doing its job.

Also, if you see ANY coolant dripping from the weep hole (not being blown back onto it from a radiator leak) then the water pump is leaking and needs to be changed.

Hope your latest discovery will get you back on the road soon. You've been diligent and willing dive into it, so my hat is off to you.

Flint.

 

[beachcruiser]

If the pu


If the pulley and impeller are spinning independent of one another then you've found your problem. Never seen that before, but if that is what has happened to yours, then for certain you've found the problem (or at least one).

In the future...to check Water Pump output you can remove the thermostat and disconnect any small heater hose, crank the engine and if you DON'T get a geyser from that hose then your water pump isn't doing its job.

Also, if you see ANY coolant dripping from the weep hole (not being blown back onto it from a radiator leak) then the water pump is leaking and needs to be changed.

Hope your latest discovery will get you back on the road soon. You've been diligent and willing dive into it, so my hat is off to you.

Flint.

It was odd. The impeller and pulley both spun so smoothly that I thought it was normal but when compared to the new unit it became obvious.
The nut that's cast into the impeller spins on the metal center shaft that passes through the WP housing. Whatever tack weld or connection between the two must have sheared.

Everything is back together less the timing covers, serpbelt, and plumbing so tomorrow should be an interesting day. Thanks again and I'll send an update shortly.

 

[nnnnnate]

Tech tip of the morning. If it will crank but not start you put on the crankshaft trigger induction ring on backwards. Don't ask me how much I paid to find that out last week.

Hope that this solves your problems and good work getting it sorted out.

 

[beachcruiser]

So to cut directly to the outcome, this appears to fall under the category of "even a blind squirrel occasionally finds a nut OR avoids becoming roadkill."

Entire front end put back together, plumbing in place and fluids refilled.... and mentally prepared for coolant to start raining down from block as a worst case scenario, or potential clogged radiator as an acceptable second tier of overheating disappointment.

It fired right up to a slightly higher idle (1500 rpms) and a CEL and VSC/Vtrac lights (likely due to sensors being doused in coolant?) but otherwise exact same consistent smooth idle as before.... but no leak. After filling and burping per your directions, cabin heat reappeared. Temp never passed 3/8 or so on the dash. I throttled up to a steady 2500 rpm, and no rise in temps. A five mile test run with some decent hills, speed variation and rpms and she's running like a top.

All this said, I should have done water pump and timing belt (and Ts!) at least 50k miles ago so this sits squarely on my shoulders for not taking care of my preventative maintenance.... I hear an Aesop fable-esque "He who avoids preventative maintence shall reap the ill outcome of his neglect...."
BUT it appears that we may have dodged a serious potential bullet, and I really appreciate everyone's assistance in diagnosing and working through the oddball symptoms. Even if it turned out as a secondary HG failure due to overheating, the assitance has been indispensable.

I'll be keeping myself attuned to any signs of potential signs of heat related symptoms but for now (fingers crossed) we seem to be on the downward slope of this. Best wishes for the holidays. Thanks again.

 

[flintknapper]

You're probably good to go. But do keep an eye on it, and expect to need to top off the radiator after you've driven it the first time or two as its hard to get it completely filled the first time.

Again....Kudos for being so diligent and willing to dive in to find the problem. Good Job!

 

[DirtDawg]

Just shows you how bulletproof these 2UZs are. Glad you didn't have to spend a ton of money replacing a good head gasket and solved your issue.

 

[ponytl]

Congrats on getting it done... always some satisfaction in knowing you fixed it... when the professional said you needed an engine....

next thing to keep an eye on is your radiator... they like to separate at the tank to fins seam... for $100 off ebay It might be the thing I'd be ready for...

amazing that the factory hoses have a longer useful life than the radiator

 

[spressomon]

You should send a sympathy letter to the mechanic that was all over swapping in a new engine/head gasket per the hydrocarbon test. "Sympathy" for his Christmas present budget that will be a little less than he originally forecasted

Glad to hear it all worked out for you. Pays to work on our own junk!

 

[beachcruiser]

You should send a sympathy letter to the mechanic that was all over swapping in a new engine/head gasket per the hydrocarbon test. "Sympathy" for his Christmas present budget that will be a little less than he originally forecasted

Glad to hear it all worked out for you. Pays to work on our own junk!

I did one better.

I went in with the water pump and the offending sheared impeller just to show him what had occurred.... he said "that's makes sense... and that's probably caused the blown HG."
You mean the blown head gasket in the truck I drove here? Odd. Drives just fine now.