Head Gasket - Headache. Help requested. (1 Viewer)

[4gundrill]

I have a '93 FZJ-80 with 196,000 on the clock. I purchased it a little over a year ago with little PM documentation. I immediately started baselining the truck and sent a sample to blackstone for analysis which showed some coolant in the oil. I then completed a compression test which showed excellent results (190-196) across all cylinders and a block test (actually like 3 or 4) wich was negative. At that time I changed the oil, drove about 1000 miles and sent another sample to blackstone. The results did show trace amounts of coolant but it was such a small amount they asked if I had done the head gasket. At this point I felt like everything looked pretty good; so I figured I would keep driving and monitor the coolant level and oil. I also did the temp gauge mod (Raventail?) just for good measure.

Fast forward about 6 months and I have only put about 3500 miles on the truck and it sat for several months while I was away for work. Since I want the truck to be as reliable as possible (my wife says I'm looking for something to fix) I decided to do a leak down test as a final test to rule out a HG failure. Cylinder #6 showed minimal leakage, less than 5% at about 75 PSI. There was no noticeable air coming from exhaust, throttle body, or crankcase. I did not see any "bubbles" in radiator BUT after about 10-15 seconds the level slowly rose and started spilling over some. At this point I assumed HG failure and started packing it up. However I decided to go ahead and check cylinder 5; it showed slightly more leakage but still less than 8-10% but no bubbles. The engine had cooled a bit by this time so that may have been the reason for slightly more "leakage". Also, I used a vacuum gauge to find TDC.

So today I took another oil sample which will be sent out tomorrow and decided to do 1 last block test. I used a spill proof funnel and allowed the truck to get to operating temp, and cracked the throttle to maintain 2000 RPM. I cut both ends out of a water bottle and inserted one end into the funnel and used the other end to insert the block tester and draw air through without pulling in coolant. I tested it at 2000 RPM for about 10 min and did not get any color change. There were a few small bubbles that came out, and I made sure to get the air from those bubbles pulled through the tester... No change. Just to check the fluid I then took it to my exhaust and within seconds the color changed to yellow.

So to sum things up....
- Truck runs great. No issues at start-up, idles good, no hesitation or stumbling.
- No visual mixing of oil and coolant. Coolant is clear (green) and oil looks like dark honey. No milk.
- No overheating, and no real coolant consumption.
- Good compression across the board, #5, 6 are both 194
- Multiple block tests performed with no color change to test fluid
- Leak down test did allow air to enter coolant on the #6 cylinder
- Spark plugs are clean, but not steamed. #6 has some white/ reddish crust but nothing major

The engine appears strong and I am going to continue to monitor and drive while I await the results from blackstone. Any idea how air can find its way from cylinder to coolant system and not show on the block tester?

 

[inkpot]

It COULD be the very early stage of a HG failure. If it were me, I would stick at dose of Bars Leak HG treatment in it and then re-examine for the bubble issue. I have had multiple good experiences with Bars, even thought some folks are very negative about it. YRMV. John

 

[baldilocks]

Possible tiny crack in the head?? I agree with the sealer treatment at this point. Or, if you like to wrench and thus is not a DD, just do the HG for peace of mind. Once the head is off you will have access to many other components you could replace or test.

 

[4gundrill]

Thanks guys. I think I'm going to wait for the results to come back from black stone before I proceed any further. If they confirm coolant in the oil I will likely pull the head and investigate. I just don't understand how it can fail a leak-down test, but still not show up on a block test. Just doesn't make sense to me.

 

[Rusco]

I had a buddy, serious anal-retentive long-time independent shop owner tech that was big into Buick Regal turbo cars (Buick Grand National?) that used a lot of boost, and Paul was always hanging basketball-sized turbos on the things. They would then go to the drag-strip and either do stupid wheelies or blow head gaskets. After a while, and many attempts at using different gaskets and head studs, he started putting some GM sealer in the coolant and was able to get three or four solid runs before they would actually blow up an engine. It was all good in his mind.
Anyway, I was talking to him a few years ago, back when I first bought the 80 I have now, and it was just starting to show some oil in the coolant. I was all ready to do the head gasket, and Paul tried to talk me into using this GM additive, that he said was developed by GM for the Cadillac iron head aluminum block motors that had persistent head gasket leaks. I didn't bite, but it was something that stuck with me....
I ended up doing the head gasket, and sure enough I had an oil leak into the coolant jacket at the main oil passage from block to head.

 

[4gundrill]

So I got my report back from Blackstone and it looks like I have a very small HG leak, which I suspected. The potassium level was at 20 PPM and the sodium was at 105 PPM, this was with approx 3500 miles on Mobil 1. The potassium is low enough that I'm not going to get in too much of a hurry, but I will start buying parts for a HG swap. This just goes to show that the block testers may not be sufficient for catching the early stages of HG failure.

I live in SD so I really don't need antifreeze except for corrosion inhibitors, do you think I may be better off switching to distilled water until I get the HG swapped? My theory is that such small amounts will likely just burn off from the oil.

Anyone recently have a HG done at SD Trux? Debating on having them do it do to lack of garage space.

Thanks!

 

[Funner]

So I got my report back from Blackstone and it looks like I have a very small HG leak, which I suspected. The potassium level was at 20 PPM and the sodium was at 105 PPM, this was with approx 3500 miles on Mobil 1. The potassium is low enough that I'm not going to get in too much of a hurry, but I will start buying parts for a HG swap. This just goes to show that the block testers may not be sufficient for catching the early stages of HG failure.

I live in SD so I really don't need antifreeze except for corrosion inhibitors, do you think I may be better off switching to distilled water until I get the HG swapped? My theory is that such small amounts will likely just burn off from the oil.

Anyone recently have a HG done at SD Trux? Debating on having them do it do to lack of garage space.

Thanks!

First off, I think your wife is right about you.
Run Coolant, add some stop leak and prep for head gasket in the next year or so. That's my opinion anyway, YMMV

 

[4gundrill]

The thing that makes me nervous is that when I first bought the truck I did a UOA at blackstone to baseline and the potassium was 145 and sodium 287. I don't know how many miles or what type of oil was being used when I bought the truck. Since then I have done two additional UOA both with blackstone and neither were over 20. I have not done anything to fix the issue, only changed the oil.

I'm not really a fan of stop leaks because of what the it can do to coolant passages in the block, head, and radiator. Are there any that are better than others when it comes to the side effects?

 

[sbman]

I happen to have a new in box OEM head gasket that I bought from CDAN sitting on my shelf. I used a cometic MLS during my rebuild and didn't need the gasket. So far no one has bought it from me.

 

[4gundrill]

I just wanted to give an update to this thread. My truck was still running fine with no obvious evidence of a HG failure. Recent Blackstone reports showed small amounts of coolant in the oil. Compression checks were very good and within a few PSI across all cylinders. However, a leak down test did have some blowby on #6. I never could get the block tester fluid to change colors.

Anyway, I knew something was wrong so I decided to go ahead with the head gasket repair before there was a catastrophic failure. I was going to do it myself but with the limited garage space I have, I decided to take it to SDTRUX and I am glad that I did. The head was out by .01, not .001 but .01. I am surprised that I did not have a more obvious failure. I ended up with a new head and an OEM radiator. I should be good for a while.

By the way, SDTRUX was great. I went to them based on reviews that I had seen here and I would highly recommend them to anyone on the San Diego area.

 

[Kernal]

Do you have an itemized list of the work done, new parts (head bolts new, reused?), cost for labor, did they machine the new head, ---?