Headgasket leak?

[The Critic]

For those of you who remember this problem, it is still going on-- I have a somewhat mysterious coolant leak on my Saturn. However, lately the leak has become large enough that it goes through a pint of coolant every other week.

I had a shop pressure test the system cold (overnight) and perform a block test, neither of which returned any signs of leakage. As some of you had suggested, the leak may not be found and other measures may need to be taken. I have not had a chance to look into it further.

However, I did a long trip at high rpm (3k+) and at the conclusion of the trip, there were traces of coolant on the engine block near the oil dipstick area. So, I think the leak is most severe when the engine is hot and being operated at higher rpm.

To narrow down the location, I pressure washed the engine compartment clean (shiny clean) and within 3 days (and only 40-50 miles of driving), I saw these spots:

Clearly, in the second picture, that red dot is Dexcool and the brown/reddish deposit is coolant, right? That area was shiny metal just 40 miles and 3 days ago.

As a side note, the radiator, water pump, heater core, radiator cap, upper/lower/bypass hoses and thermostat have all been replaced within the last 20,000 miles.

So, where could that coolant be coming from? An external headgasket leak?

Thanks.

 

[Jim 5]

Mike,

You might want to PM eljefino. He seems to rebuild these saturns on a monthly basis. Head gaskets seem to be a problem, and I bet he could help point you in the right direction.

FWIW, I had a mysterious coolant leak on my '89 4Runner many years ago. I'd get a little puddle of coolant on the ground everytime I turned off the truck when it was at operating temperature. When I looked under the hood, everything was always dry. Finally I clued in and had somebody shut it off while I was looking under the hood with a flashlight.

Turned out to be a loose lower radiator hose, as a radiator repair had been done a little while before that. The coolant would shoot out at the lower hose and the hot radiator/hose would instantly evaporate all signs of where the leak was. It was literally a matter of tightening a loose gear clamp that the repair shop didn't tighten, and the problem went away forever. The point is, the place where it's leaking may be hot enough to evaporate the evidence of where the leak is, so you need to be there looking when the leak happens. Right after shut-off, at least in my 4runner, there seemed to be a momentary pressure surge in the cooling system - but under normal pressures while driving....no leak at all. That was why it was so hard to diagnose.

Anyhow, that may not be applicable to your problem, but I thought there may be a chance given a bunch of hoses have been replaced recently. You may want to just check the tightness of each hose clamp. Good luck and let us know if you can track down the leak!

 

[Cutehumor]

you can do a UOA critic to make sure it's not a headgasket leak

 

[onion]

Originally Posted By: Cutehumor
you can do a UOA critic to make sure it's not a headgasket leak


A UOA might help to diagnose or eliminate an INTERNAL head gasket leak (into the oil or into a cyliner). But head gaskets can also leak externally (and this leak appears to be external)... that won't necessarily show up in a UOA.

 

[addyguy]

14 year-old car wth 150k miles?

I wouldn't waste a lot of time worrying about this one. It appears to be a minor, external coolant 'weep' from probably the HG.

I'd be inclined to try carefully re-torquing the headbolts to see if it helps. A UOA would be useful to see if coolant is getting into the oil.

 

[Kestas]

Off-topic -- I always get a kick out of the lost foam casting technology, and how castings look like styrofoam.

 

[JHZR2]

Yeah Id do a UOA to see that it is not getting into the oil, and from there not worry much. You might put in the GM cooling system pellets to help plug it a bit, but beyond that, I see no good course of action.

I have a cooling loop around the TB on my 91 BMW. One of the corners has a crack that weeps fluid slowly. After time the coolant evaporating off left enough residue that it plugged itself.

 

[SLCraig]

Do you use a cleaner in your pressure washer? That block looks like new.

Not sure about your leak there, what type of coolant are you using?

 

[The Critic]

Originally Posted By: addyguy
14 year-old car wth 150k miles?

I wouldn't waste a lot of time worrying about this one. It appears to be a minor, external coolant 'weep' from probably the HG.

I'd be inclined to try carefully re-torquing the headbolts to see if it helps. A UOA would be useful to see if coolant is getting into the oil.

The concern is that I am having to top off the coolant every 50-100 miles, each time about 12-16 ounces worth. The engine also seems to get warm quite easily when claiming even small hills, though it has yet to come close to overheating.

Originally Posted By: SLCraig
Do you use a cleaner in your pressure washer? That block looks like new.

Not sure about your leak there, what type of coolant are you using?

Usually I use simple green diluted 1:10 but this time I just went to the local coin-op car wash and blasted it with their super watered down soap solution, followed by the high-pressure rinse option. I clean the engine compartment quite regularly so it stays reasonably clean.

I am use a GM approved Dex-Cool product for coolant.

 

[Jim 5]

Originally Posted By: Kestas
Off-topic -- I always get a kick out of the lost foam casting technology, and how castings look like styrofoam.


I really noticed that as well. I was wondering about why the block looked like patterned vinyl. I didn't realize they used lost foam casting on these. Thanks for pointing that out.

 

[Vikas]

If you are willing to try magic elixirs, there are few ones with decent reviews. Once you have decided that you will take the head off, try the snake oil before proceeding. If you are interested, I will find the pointer from youtube.

- Vikas

 

[fdcg27]

If you have an external HG leak, a decent stop-leak product should fix it.
If you have an internal HG leak, it probably won't.
Since you are clearly losing coolant, you should see some symptoms of an internal leak, like a white exhaust plume, as well as overheating.
If you aren't seeing any real symptoms, and you are in fact losing a fair amount of coolant, you could try a stop-leak product, and see what happens.
Might solve your problem.

 

[morris]

black pepper

 

[PandaBear]

filler item probably won't fix a leak that's 1 pint every week. You can try but I don't think I'll rely on that. If you want to replace the HG, I know a guy that did mine for only 1k with head milling. If your head is fine, it'll probably be cheaper by a couple hundred.

 

[eljefino]

How big are your hands?

The issue with head gasket jobs on these is removing the timing cover. One needs little fingers to get at the approx 23 10mm bolts stuffed in between the motor and fender. If you want to DIY the gasket is only $20. You're gonna want to do all new timing chain/tensioner/guides when you're in there; the tensioner never cooperates. I would not mill anything but you should of course check for flatness with a straightedge or whatever.

When I have had slow coolant leaks on a motor, the coolant evaporates and leaves a whitish "salt" behind. Not sure if Dexcool behaves this way. You should be smelling burning antifreeze if it's dripping as it is.

 

[SAATR]

Head gasket or possible casting porosity causing a leak at operating temperature/pressure. What is the highest point on the motor that the coolant tracks to?

 

[Chris142]

Dexcool in a car specked for old green coolant?

 

[eljefino]

96 was a transition year for s-series and dexcool. Assuming he has his original rad cap, it tells the tale.

Build date?

 

[addyguy]

Would re-torquing the headbolts, like I suggested, possibly cure this, if it is just a minor leak?

I know if the HG is 'gone' it won't, but this still seems minor....

 

[The Critic]

Originally Posted By: eljefino
How big are your hands?

The issue with head gasket jobs on these is removing the timing cover. One needs little fingers to get at the approx 23 10mm bolts stuffed in between the motor and fender. If you want to DIY the gasket is only $20. You're gonna want to do all new timing chain/tensioner/guides when you're in there; the tensioner never cooperates. I would not mill anything but you should of course check for flatness with a straightedge or whatever.

When I have had slow coolant leaks on a motor, the coolant evaporates and leaves a whitish "salt" behind. Not sure if Dexcool behaves this way. You should be smelling burning antifreeze if it's dripping as it is.

Thanks, and yes it does leave white-ish stain marks near the oil dipstick area. They come and go though.

Originally Posted By: eljefino
96 was a transition year for s-series and dexcool. Assuming he has his original rad cap, it tells the tale.

Build date?


11/95 with green dot. Shouldn't matter though, as wolfman said they were back-speced.

Originally Posted By: addyguy
Would re-torquing the headbolts, like I suggested, possibly cure this, if it is just a minor leak?

I know if the HG is 'gone' it won't, but this still seems minor....


How much time to do that? Aren't most head bolt one-time use and TTY though? Wouldn't they break if I tried retorquing them?