Still losing coolant

[arcter]

Ok guys, this is starting to really bug me. The car is still going through quite a bit of coolant. In the past week it's gone down an inch or so. The shop that put in the new radiator said that the cooling system held pressure. I don't see anything in the oil, and I don't get smoke while driving. I do get some in the morning but it mostly looks blue. Car drives perfectly fine. Any ideas? No leaks either.

Other problems: rough running when first started when cold, stops after a few seconds of giving it throttle.
Temp gauge shows car as 1/4 usually, never middle.
Idle fluctuates between 600-900.

[Ryann]

So long as your system has been properly bled, you know it's going either in or out. To check for internal leaks I'd pull my plugs and look for white chalky deposits. For external leaks I'd take a hard look at things under the intake manifold based on what I've read here.. I'd also go get a large piece of white plastic, like maybe a huge garbage sack, and park on it overnight.

[cristimm]

Temp gauge shows car as 1/4 usually, never middle.

To solve this problem you'll have to replace the thermostat.

[BlueBMW]

Another test you could do is borrow a coolant system pressure tester.  Pull your spark plugs and pressurize the coolant system overnight.  Put about 15 - 17 psi pressure on it.  After sitting overnight, check your cylinders with a flashlight and see if there is any coolant in them.  You may have just a slight leak into your cylinders that's enough to make your coolant slowly disappear but not enough to smoke.  If there is coolant, then you can suspect head gasket or cracked head.  If there is not, then you can probably rule those possibilities out.

Where do you live?  If you're somewhere reasonably nearby maybe I can come by and check it out.

[flyinglizard]

If you can't see the leak, then it must be burning it....
    Look for white plugs, it takes about 1/2 gal coolant lost at one tank of fuel to turn the plugs white.
 Pull the head, You wont trust this car untill you have. Get on with it.  

IMHO. MM

[arcter]

Okay guys, here's the deal.

I pressurized the system and found water in the cylinders. Not much, but obviously enough. I am suspecting a head gasket job. Lots of smoke comes out the back now, more after adding the pressure. So I'm certain I have to pull the head.

So I'm at least going to do that. I bought an extra cyl. head for insurance and I'll buy the head gasket this week. I have a few questions though. The person I need to have do this job isn't immediately available, I think because of finals coming up (college student). Anyway, he's the only way I can get this done because he's so much cheaper. How long can I safely run with this condition before I do damage to the engine? I know if it overheats I could crack or warp the head, but I have that extra as insurance for that reason. But is there other damage I could do that would be irreparable or super-expensive?

Here's the other question. Should I think about doing a full or partial rebuild? If so, which one? I think I am burning some oil, but it could just be valve guide seals because I only see the smoke in the morning. But a while ago when I had my cold starting problem when cold a shop told me it was likely carbon buildup and they recommended new valve lifters and a valve job. I'm starting to wonder if the cold start problem is just related to the coolant issue and maybe this diagnosis was wrong...

Any ideas? Thanks!

[BlueBMW]

The bottom ends seem pretty tough on these motors.  If you have to run it a bit longer you can, but it'll probably get worse the longer you run it.  

The last car I saw like this was a 318ti my co-worker bought.  It ended up being a cracked head, but he had the symptom of cylinder pressure going back through the coolant system (BIG bubbles coming out of the expansion tank)  I'd say probably just a blown head gasket and maybe a warped head, hard to say though.  Good move on getting the extra insurance.  

If you dont mess with anything bottom end, you may want to at least inspect your timing components since you'll have the head off already.

Or.... build it up and boost it!

[arcter]

Hey thanks for the reply Blue. So if I run it a few weeks or so more, what will I most likely end up having to do? Just wanting to make sure I won't mess anything up beyond repair (or at least beyond repair for reasonable $$$).

Just want to know what would be the smartest. My timing chain stuff is all new, as is the radiator... and a bunch of new hoses and stuff. Basically I just want to make it as reliable as possible at this point! I have a daily commute of about 80miles round trip. It's been doing it but I've put quite a bit of money into the car so far and now just want to make it reliable as it can be. I know it's not a Civic but I knew that before I bought it

[flyinglizard]

If you are going to keep the thing, do the chain and rails as you do the head. Some of these have a very minute corrosion leak,  some leak between the center cyls, some have the profile leak . I have money on the center leak.  

 If you address the head, chains and tighten the oil pump stuff up, the only other thing that will stop the car, is the fuel tank and pump.IMHO. MM
 PS I would not run it that far  pushing water.  As soon as the oil gets  milky white, the rod bearing will start to go away

[arcter]

Oil isn't milky white yet, haven't noticed that at all. I'll keep an eye on it and keep checking it each day. I'll definitely stop driving it once I see that.

[///M3Mike]

I'm having the same damn issue.  Haven't done a pressure test yet....need to find someone I can borrow a tester from.  I'm getting coolant dropping about an inch below the KALT mark, but my temperature is spiking at the 3/4 mark.

[locknload]

I don't recommend driving it as the coolant can find its way into your oil as already discussed.  However, if you have to drive it, I'd loosen the radiator cap so it doesn't pressurize.  That will keep the hot coolant from being forced into the engine when its not running and also help prevent the cylinder pressure from overpressurizing your cooling system and causing more damage.

[arcter]

How obvious is the mixture of oil and coolant on the dipstick when it's gotten bad enough not to drive? I definitely haven't seen what I'd call "chocolate milk" yet.

[Ryann]

I'd say chocolate milk on the bottom side of the oil filler cap is a better indication for you at this point.

[arcter]

Yeah I see nothing on either the stick or oil filler cap.