TheAllusionist

So a couple of weeks ago when it got into 100s I installed a new AC compressor, took the car out, drive in "touchless" car wash and visited my mother. When I got back out to the car it didn't want to start or run well, it was crapping out. I figured it was hot and noticed coolant dripping on drivers side on ground. Drove it home and in the garage with door closed I noticed it was blowing white smoke. I shut it down and waited a few hours and started opening up coolant resevour and it was still under pressure and hot, so I left car alone until morning.

Next morning looked at dipstick and oil cap and didn't notice water, checked coolant, didn't notice oil, so I hoped maybe it wasn't a blown head gasket. I had to go on family vacation the next week and didn't want to deal with it or let it ruin my mood for the trip so left it alone.

Today I had a bit of time and ran compression test (Harbor Freight tools so who knows how good the readings really are) and I got the following:

Cylinder 1 = 105

Cylinder 2 = 105

Cylinder 3 = 105

Cylinder 4 = 112

Plug one looked the leanest with two and three a nice light chocolate brown. Plug number 4 looked like it could have moisture on it beaded up and cleaner than the rest, but it had the highest compression. So I put everything together and fired it up and let it run until fans kicked on (wanted to verify they were working) and checked number 4 plug and it seemed to be dry, but very clean. Coolant tank was under pressure, but that may be the normal if it got warm enough for fans to kick on.

Perhaps car has to get hot enough for the head gasket to leak? Not certain what my next step should be, leak down test?

Attached photos of compression test and spark plug #4 the one that seemed perhaps wet when I first took out plugs, but looked try after running engine for a while. Concern is it looks pretty clean.

Thanks in advance for any input you may have.

Auto_Werks 3.6

Plug pics look pretty good actually. Those compression numbers seem really low, ,but maybe that's the cheap gauge. Blowing white smoke and running rough doesn't sound good at all though. I think if you go to a radiator shop they can test the coolant for exhaust gasses, that might help. Also a quality leak down tester might help you figure out if there's a leak into the cooling system

TheAllusionist

Thanks, radiator shop or mechanic testing water seems like a good idea as it runs fine now. Car only has 48,000 miles but that doesn't necessarily mean much I am finding out.

Techno Duck

If the compression test was on a cold engine it will give lower numbers. If you have water leaking into any cylinders it will show high, so that's why #4 may have given slightly higher results.

If you run the car up to normal temp, then shut it off wait a few hours. Pull the plugs and look down into the cylinders, you might see coolant pooled on top of the pistons.

Another thing you can do is use a cooling system pressure tester. You can rent one from your local Autozone or OReileys. Pressurize the cooling system to 10-12psi and let it sit overnight. If it holds pressure you are probably fine. If pressure drops, pull the plugs and check the cylinders.

raleighBahn

Agree - do the pressure tester and see if you can get it to leak. You may want to warm it up enough to open the thermostat.

Have you gotten underneath with a light to get some idea of where the leak is? Could just be coolant burning off.

Tom M'Guinn

Sounds like you had an external leak, so a pressure tester will help track that down. I'm a bit suspicious that is started driving poorly after the car wash -- suggesting maybe the ignition got wet and/or water entered the exhaust somewhere -- especially if it's running fine now. I'd drive it for a week and recheck for mocha-colored goo under the oil cap. Or if you are impatient (like me), route the coolant overflow to a plastic soda bottle under the hood, and see if you can induce overflow by boosting hard (after fixing the external leak and bleeding the system well). If you can putt around all day without overflow, but then get overflow as/when you run it hard under boost, that's a near-sure sign of a HG going out. High combustion pressures will breach an iffy gasket long before a pressure tester will...

TheAllusionist

Thanks everyone, looks like tracking down the leak, it did not leak yesterday when I ran it long enough to get the fans to start up, but may not have been enough hot enough for thermostat to open or leak to leak. I will look into renting a pressure tester and research how to bleed the system.

I to wondered about water getting in some where during automated car wash, but also was being careful and trying not to do more damage. Hence after car had been sitting for more than a week in the garage (just got back home), I took the DME relay out, pulled plugs and did cylinder pressure test. Probably should have started it up and let it run a bit before doing it, but I wanted to check things out first, worried that two side by side cylinders were going to have real low pressure.

Once again, thanks for the input everyone, helps me not just throw money at it! LOL That is what my wife thinks I do anyway! LOL

rlm328

Check your exhaust, often when you have a blown head gasket and you have coolant blowing by the gasket you will get "splurge". You can either put a clean sheet of paper to catch the splurge or if it is bad you can see in on the drive way.

The best way to define splurge is wet oil spit that comes out the tail pipe. It is most prominent when you start the car.

refresh951

+1 Great advice

TheAllusionist

Thanks everyone, plan on renting pressure tester when I get time. I did look for moisture coming out of tail pipe. Nothing noticeable at this time.

I will report back after I have had a chance to pressure test and bleed system.

Stephencs601

Jon, that was good advice. How are things on the west coast. Anderson and I are still going driving on Sundays.

schip43

White Smoke?? Is a Head Gasket. I don't see a work around that myself??

TheAllusionist

Just got back from renting a coolant system pressure tester, will go hook it up, pressurize to 10-12 PSI and leave overnight. Thanks everyone!

Tom M'Guinn

Be sure it's fully bled first and clamp the overflow hose. I've never needed more than 5-10 solid minutes at 15psi to find a leak, and normally not even that long. Not sure it's worth leaving it all night if the pressure holds with no drips after 10-20 minutes. Those testers tend to bleed off pressure themselves (through the bladder I think) so not sure it's realistic to ask it to hold pressure over night, though it should be drip-free no matter how long you leave it.

Edit: I was talking about external leaks and just realized you're looking for a HG leak too, so suppose it's possible leaving it overnight at a lower pressure might help sniff that out as TD says...

TheAllusionist

Well, I bled the system, lots of air, didn't find any external leaks, coolant that does come out comes from area of overflow hose so I am assuming it comes from there, maybe cap should be replaced. Didn't hold pressure all night, but more importantly after doing all this and starting it, light puffs of white smoke comes out of tail pipe and feels humid, not quite like dryer vent exhaust, but slightly similar so I am probably going to assume the worst, that I have a slight head gasket leak/blown head gasket and part the car until I feel ambitious to tackle the job or have the money to have it taken care of.

My cam cover has a leak somewhere I believe and needs fixed, I have a ported intake matched to an oversized throttle body and have wanted to upgrade the turbocharger, probably should just do it all at the same time, so figure car will be parked for some time.

Thank you everyone for you help and advice.