engine and drivetrain Cooling system issues

[mbaze]

Looking to troubleshoot some weird behavior in my 1971.

a. When you take off the radiator cap when the engine is stone cold, you get a big whoosh of air as it depressurizes. I've never noticed that with any other car.

b. The motor runs a little hot, at least 2/3 of the way toward the red zone.

c. Once and only once, when the car had been sitting for three cool days, it was hard to start and emitted a minute-long plume of white smoke (alas, I did not do a smell test). It's never happened since.

d. My mechanic has detected moisture in the air filter area.

e. The heater works, but not very well.

f. The motor does not idle well.

The BMW shop pressurized the cooling system for 30 minutes and pulled the plugs and did not detect any untoward moisture. So there is no clear evidence of a cracked head or blown gasket. But we can't rulel it out either. Something seems amiss.

Ideas?

Michael

[golf73]

how long have you had the car? how many miles since major engine work? know much about any previous or recent work to the cooling system? has it always been running at 2/3 mark or is this recent? are you losing any coolant? could be a bad water pump, clogged radiator, i.e. poor coolant flow or coolant leak somewhere. could be a number of things, but sounds like you might have cracks in the head. you could test for exhaust gases in the cooling system, do a leakdown test. likely you need a valve job anyways if it's got high miles...i hope it's not true but a minute of white smoke plumes isn't a good sign either.

[mbaze]

I've had the car about a month. Just completed a major service at a reputable BMW shop. The car originally came with an aftermarket temp gauge mounted on the dash. The garage fixed the original gauge today.

The coolant has dropped a little over the past 10 days or so; it's still above the core. But there's also a small leak near the heater control valve. So it's hard to tell where the coolant has gone.

We (the shop owner and I) are both a little perplexed by the pressurized system when cold. Seems unusual.

[antiaem]

the whoosh of air when cold is a bad radiator cap. its not pressurized, its in a vacuum. the cap is supposed to hold pressure when hot, release pressure when too much occurs, and let the system depressurize as it cools. its not doing the latter...possibly...cheap to find out though at least. btw mine runs at 2/3 hot also. i just got this car and am not entirely sure this isnt normal, then again i havent asked anyone.

[ClayW]

the whoosh of air when cold is a bad radiator cap. its not pressurized, its in a vacuum. the cap is supposed to hold pressure when hot, release pressure when too much occurs, and let the system depressurize as it cools. its not doing the latter...possibly...cheap to find out though at least. btw mine runs at 2/3 hot also. i just got this car and am not entirely sure this isnt normal, then again i havent asked anyone.

I second the radiator cap replacement. It's not working properly. Those things tend to be one of the most overlooked and most cheaply replaced parts on any car.

Secondly, replace your radiator. The original 2002 radiators clog with time, and it's just better to replace them.

If you want a bit more insurance, buy one of Curt Ingraham's upgrade radiators or use a 320i radiator. You'll have to drill a few new holes for the 320i radiator, but it's the cheapest solution. Hell, one of Curt's radiators is cheaper than what Bavarian Autosport charges for a stock one.

The leak up by the heater valve is a bastard. You might need a new valve, but it could also be a leak in the little hose between the valve and the heater. If you don't remove the entire box from under the dash (huge pain in the @$$), then you have to be REALLY careful and get to it from the engine bay. Be especially careful not to break the little plastic tab that holds the heater valve.

Good luck!

[mbaze]

Thanks all for the replies. I trust my mechanic implicitly. He's been doing 2002s for 25 years. So I'd be surprised if he put on the wrong cap (he replaced the old one). But I'll raise it with him.

Any idea how much Curt's radiators go for these days?

[golf73]

Thanks all for the replies. I trust my mechanic implicitly. He's been doing 2002s for 25 years. So I'd be surprised if he put on the wrong cap (he replaced the old one). But I'll raise it with him.

Any idea how much Curt's radiators go for these days?

i'm curious to which shop you're going to. i used to live in oakland.

6 months ago curt's radiators were $425 minus $75 for your old core. i'd be curious to see how much a good radiator shop would charge to re-core your old one with 3-row innards. you could paint it yourself with high-temp black radiator paint after they're through with it and re-use the new cap your mechanic just installed. i would have probably gone that route but the 2002 is my only running car and i needed to swap it in and out immediately.

another alternative is from beyond 02 for $229, i think it's the 320i radiator but you could contact him to be sure. http://www.beyond2.com/parts.php

[mbaze]

I'm going to Bavarian Professionals in Berkeley and working with Michael, the owner.

[golf73]

cool. never heard of them but looks like a nice shop from their website. i was gonna cringe if you said berkeley motor works. you might try alan at H&B on fourth st. if you want a second opinion from someone who knows 02's.

[Beaner7102]

Is you timing advanced too far, if your timing is out it can cause a car to run hot, like the 2/3rds mark you say.

Just a thought, and no cost to fix.

Beaner7102

[Tangarine-Dream]

Dude,

Work with Curt, he is local. Trust me, that is your best option. There are some things you don't want to cut corners on. An overheated car can cost you $$ later. Curt's the best! Good luck.

[jgerock]

What about a stuck thermostat? Or bad radiator hoses (large diameter) that collapse under vacuum from the water pump?

My coolant "branch" fitting that mounts on the cylinder head was full of crap when I removed it (makes it worse on a tii).

If you have the $$, I'd replace all the hoses, t-stat, rad. cap and flush the radiator as a starting point.

[ClayW]

What about a stuck thermostat? Or bad radiator hoses (large diameter) that collapse under vacuum from the water pump?

My coolant "branch" fitting that mounts on the cylinder head was full of crap when I removed it (makes it worse on a tii).

If you have the $$, I'd replace all the hoses, t-stat, rad. cap and flush the radiator as a starting point.

True. Start with the cheaper stuff.