spazegun2213

While I should probably post this in the regular c5 forum, I figured you all will probably know as much or more.

Background:
Went to button Willow last weekend for a track day... it was 108 degrees out and the car suffered. Any time I really pressed over 80% the temps went sky high. This was compounded by a failing fan relay that caused the car overheat while pulling into the paddock. *sigh* So after seeing 270, I figured the head gaskets were toast. I took the car out one more time it was consuming water at a ridiculous rate, so that was the end to my weekend.

Problems:
I decided to buy a combustion gas tester kit to confirm the Gaskets were toast (better to be safe than sorry right?). I started the car up and warmed it up to 180. While doing that I noticed that the Oil pressure went sky high when I reved the throttle (70+psi). While this motor is new to me, my last ls-6 never did that. But the car also consumed a gallonish of distilled water in 5min of warming up, causing a low coolant light. I used the tester thinking surely it will come up positive for a leak, and nothing......

Looking on the ground there are no leaks, all the hoses check out, etc. Only "weird" thing is a fluid is clearly leaking onto the drivers side headers at the back of the motor. I cant at all see what it is, but there is not really a smell (leading me to think this might be water?).


So between the unusually high oil pressure, the fact that the car consumes coolant, and there are no visible leaks, I'm at a loss for what exactly happened.

Any ideas guys? No matter what happens the car is getting a serious cooling system update (I have a big alu rad).

rbl

Pull the plugs and check for water in cyl. If so, probably some bent goodies.

sperkins

Are you using water or coolant?



The high oil pressure could be the engine trying to pump a mix of water/oil sludge if the water is leaking internally.

spazegun2213

Same thing to me. I run distilled water (and water wetter when I have some).

I never thought the water could be causing the high oil pressure.... but with that mush water leaving one system, its got to be going somewhere.

bb69

If the water isn't on the floor or in the oilpan, it pretty much has to go out the exhaust. It could also be leaking onto the exhaust and turning to steam before hitting the ground. Either way, a gallon in that short amount of time means you're pulling the heads.

spazegun2213

is the consensus still that the OE GM head gaskets are still the best bet?

redtopz

That's what I use. You should drain the oil and see what it looks like. At a minimum you need new head gaskets. How hot were you running on the track? Sound like the fan issue is a separate problem. Also, what do you have for an oil cooler. Sorry to hear your first day back out was such a PITA.

froggy47

I had an m3 with blown hg so went thru some of this stuff.

1 When I rev my cold ls6 engine I can get 65+ psi oil press easy & my engine is 100% so I don't really count that as anything. The press gauge can be off several psi on any vette.

2 My blown hg leaked coolant into the chamber & right out the exhaust, never got any in the oil. I would drain the oil and look for coolant there.

3 The HC tester may or may not be that accurate.

4 Compression test and or leak down test to me is the best gauge.

5 If there is water in the oil you best look to the bearings also.

6 If you think a gal. of water went to the oil pan that would certainly show on the dipstick, yes?

spazegun2213

There was a spot where I hit 260+ coolant temp. The fan is a separate issue, that looks to be a stupid relay. Freaking $5 part is about to cost me a lot more than that.

Looks like I need a compression test, but I'm not sure how I'd read the results. I'd assume a HUGE pressure leak is something serious (bad rings?) but a smaller leak would just be the Head gaskets? How would I check the bearings?

froggy47

Well, b4 you do that, pull all the plugs, label them to each cyl. Look for one or more that looks like it's been "steam cleaned". That one (or more) has water getting in.

B4 I put my race radiator in I had coolant temps of 255-260 and oil 290+ for a few laps & didn't hurt. Not saying what you have but you need step by step analysis & then the picture will add up.

IIWM I'd look at ALL the plugs now, even the hard to get ones.

I am not a mech but I would think on a comp test rings would mean all the readings would run a little low, one or two big drops in compression would be your hg.

Pull plugs. Also I would pressurize the cooling system and check again for hose or other area leaks. That's easy. I would do that as #1, then plugs, then dump oil.

RX-Ben

Not to miss the obvious, but was your exhaust smoking (or "steaming") at all after the issues started?

+1 on Froggy's points. As Scott and Froggy are touching on, water makes a crappy substitute for the oil bearings that usually support the crank, so you may need take things apart and look at your main (and maybe cam) bearings BUT as mentioned, first take a look at your oil for evidence of water.

GM MLS is a good bet and not a pain to install (compared to the prep of a Cometic).

Timz06

First check for water in the oil. If you take the fill cap off while it is running and hot you will see steam come out if water is getting in.

If you didn't run the car very long you should be ok. Also, not sure why the fan would be an issue if the car is moving.

Tim

wallyman424

The other thing to make sure you check is the plug at the back of the head right behind the intake manifold. Its in the same spot in the back of the motor as the crossover pipe is on the front. If that's leaking it could be causing these problems.

froggy47

Just another thought, I would not run the engine any more till you know what is going on.

If there is water in the pan the oil will float on top, so when you crank her up the water will be the first thing sucked up by the pump and sprayed all over the engine as "lube" if you catch my drift.

flink

If you can blow 100 PSI into the cylinders, that can tell you a lot. Suitable adapters come with leakdown testers. For each cyl, rotate the crank to TDC, chock the wheels, put the trans in 6th, apply 100PSI via the spark plug hole.

- You can detect ring, exhaust valve or intake valve leakage by listening

- If the coolant level in the reservoir rises, that cylinder has a leak into the water jacket

- Cover the neighboring cylinders' spark plug holes with your hand. If the hissing sound changes, you have a cyl->cyl leak

I've never worked out how to detect cyl->oil leaks this way.

fatbillybob

Lots of clues can be had before doing all the work of a teardown

Based on your report order of importance:
leakdown test
coolant system presssure test
oil report


an amazing amount of water comes from a warming up car tailpipes

yakisoba

Head gasket comment: The gasket is highly variable depending on what has been done to the heads and the block deck. If you have stock heights in both places, the stock gaskets should be fine. Follow the torque guidelines for either the stock twist bolts or the ARP studs you should be using. Pulling heads isn't all that hard to do, but requires great levels of cleanliness. Have a vacuum and an air blower handy and know when to use each one. A good magnet can help too.

travisnd

The coolant temp sensor port is at the front on the driver's side. The only thing coolant related at the back of the head is the steam port. On the 2001+ motors the rear ports are plugged. Check those fist along with all the other stuff people have mentioned.