My Stop Leak Situation

[cjones]

Would like to know what experiences those on the board have with either stop leak or other similar products when used to plug coolant leaks.

So, I bought a 99 Suburban from a private party that basically lied about the condition of the vehicle. After some investigation, I found out that the vehicle was purchased from a used car dealer with a blown head gasket (this was fully disclosed). At the time of sale the vehicle had a coolant leak in the rear of the engine and was diagnosed with a bad head gasket, oil getting into the coolant. Sometime after that, the leak has disappeared and the Suburban was resold to me. I test drove the Suburban and it drove reasonably fine. No leaks and no overheating. Since I didn't know about the head gasket I've put about 600 miles on the Suburban with absolutely no problems. Since, I found out this problem I parked the Suburban so I don't do further damage and I scheduled an appointment with my diesel doc for a compression gas test next week.

I don't know where the leak was from and I don't know what was used to plug it but I assume it was a stop leak like product.

How long will stop leak work and does it mean the block is toast from clogged passageways? Can you drain or clean out stop leak from the block? If the stopleak was used to plug a bad head gasket, will I be doing more damage by running the vehicle or has the damage already be done?

Thanks for any insight and buyer beware.

[rapidoxidationman]

Any odds that the HG was replaced before the truck was sold to you?

[cjones]

It's an option that work was done, but seller made no mention of it and seems that would be a selling point to mention work that was done. There were no receipts for the car.

[Kennedy]

I would suggest an oil analysis to test for presence of coolant in your oil. This is the most critical issue at this point. It is odd to get oil in the coolant, but common to get coolant into oil.

[Liftgate]

Oil pressure is higher than coolant pressure. There might be a crack somewhere in the block, oil gallery passage that is causing this. Just a thought.

[cjones]

Is there a home Oil Analysis kit or should that be done at the mechanic? I'm used to seeing the results of coolant in the oil, such as the tan mixture. This oil on the dipstick is pure black, does the thicker oil hide the coolant better?

On the oil pressure. I've noticed that this rig runs a higher oil pressure on stratup 50-70 (based on the dash gauge). Once it warms up the pressure drops back down to approx 40. Any correlation? My 94 seems to have much more consistent oil pressure regardless of operating temp.

[trbankii]

Higher pressure on startup is normal. Oil is thicker when cold and thins out when it heats up.

I'm pretty sure that Blackstone Labs was one of the ones mentioned in the past for doing oil analysis.

[cjones]

So, took the Suburban to Diesel and Machine here in North Lewiston. I've used them many times in the past and have been pleased with their knowledge of 6.5 Diesels. It seems many of the guys working there have been there long enough to experience the demise of the 6.5. My only fault is that because of this they seem not to push any of the improvements that have followed, such as improved blocks.

They didn't find anything on the block that would indicate or not indicate a blown head gasket. They did confirm that something was added to the coolant but couldn't tell what the product was. They also came to the same conclusion that I did that the engine is running great and has no leaks. I guess this is good news but feels like the part of the horror film where all is calm but you know something bad is about to happen.

Here's a more detailed list of what they found:
1. Code P0236: This should be the wastegate solenoid that I found broken and is in the process of being fixed. On this note while on the test drive they mentioned boost pressure was 35psi. If the wastegate solenoid isn't hooked up what pressure is the computer reading?
2. Code P0250: Fuel Pump Valve. I'm not sure what this means yet.
3. Coolant Temps: On warmup coolant temps rose to 220 then fell back to 210/208 where they were maintained. This has been the case since I bought the rig. I assume that the thermostats are 210 and not 190.

From here I think I'll drive the beast until she gives up the ghost. I plan on flushing the coolant just in case my mysterious additive likes to keep working in places I don't want it to. I'll keep an eye out for water in the oil and see what happens.

[Yukon6.2]

Hi cjones
If it was my truck i would be inclined to not flush if you know something has been added to seal a leak.Flushing may produce that leak,so be prepared to have to fix something.
You can test the ph leavel in the coolant and adjust that with additives.
I have a Mack truck with a V8 500 in it,one of the heads has an edge the salt on the road can get at the gasket,it started leaking to the outside,anyhow we are way off the beaten track up here,and i was advised to try some bars leak in it before tearing off the head by a mechanic at a shop that did Mack work.
Never had it leak again.
Drive it,get some roadside asistance for towing if you venture far from home.
If you suspect problems start saving for a replacement.
Good Luck
Thomas

[Kennedy]

Oil pressure is higher than coolant pressure. There might be a crack somewhere in the block, oil gallery passage that is causing this. Just a thought.

Yes but there really is not an oil to coolant interface where they could swap readily. Additionally when the engine is shut down there is no oil pressure but there is coolant pressure remaining as well as gravity.

My fear would be that the block cracked up the cylinder wall from one of the main webs and was "raining" coolant into the oil. Even a smal quantity can be very destructive to the bearings and will not be readily visible. if it's using Dex Cool it will likely make a gelatin like sludge in the breather in my experience.

Predictive Maintenace is the oil analyzer that I use. There are quite a few others as well. A couple that come to mind:

US Oil Labs
Oil Analyzers