Hi,
my problem is that when I drive the 94 325i, after about 30 mins the temp gauge hits red, also what looks to be white smoke (could be steam) starts to come from under the intake manifold and out of the exhaust. At first I fill up the the coolant reservoir, but after it overheats a lot of the coolant is missing from the reservoir, but none leaks onto the ground. Any advice would be greatly appreciated. Thanks in advance.

your head gasket is gone. your waterpump has more than likely failed on you, and your thermostat is likely gone bad. how many times have you hit red? your head may be scrap metal now its warped so bad. i say this because the head is aluminum, and the block is cast iron. they heat and expand at different rates, causing some deformation to take place, because they are bolted together and cant really spread apart the way they try to.

take it to a shop and tell them to do a headgasket job (and resurfacing if needed) and change the water pump, and thermostat as well. unless your comfortable doing these things yourself. and ill go ahead and tell you they are pretty in depth jobs, and not for someone that has never wrenched on a car before. and ill go ahead and tell you...it wont be a cheap fix.

check the oil, is there coolant in it? look in your coolant reservoir do you see oil in there? both of these are signs of a blown headgasket.

head gasket is probebly gone..or most likly your thermostat gone bad...does it stay on red or does it go back down ??..because i had the same problem with mine and it went back down and found out that my thermostat went bad..but since u said white smoke that can either be a that ur head gasket is blown

prob a head gasket. but i'd do a compression test/leak down test and find out whats going on

yeah i had a feeling it was a head gasket but i definitely didn't think it could be the head. is there a way to find out if its the head without taking it to a shop? compression test would probably do that right? usually when it goes to red after about 30 mins it stays there. also, i tested the thermostat and it was fine. so im thinking water pump and head gasket replacement. i've worked on different cars plenty of times so im wondering how long of a job it would be. but with school i'll probably be too busy to work on it. i'm thinking about an independent shop cus bmw will probably charge me an arm and a leg, lol.

if your going to be doing the waterpump anyways might as well do a whole cooling system overhaul

if your going to be doing the waterpump anyways might as well do a whole cooling system overhaul
what, besides a water pump and thermostat, would a overhaul on the cooling system consist of? i know that the hoses and radiator are new, but what else would it require?

prob a head gasket. but i'd do a compression test/leak down test and find out whats going on
I was actually looking through a harbor freight ad that comes in the newspaper and they're selling a leak down test kit for about 30 bucks, im thinking that sounds better than taking it to a shop to get done.

Ok im probably gonna end up doing the head gasket.
But the parts store is giving me two choices on the head gasket and i dont know which is mine.

1. 1.75mm thinkness for $49.99
2. 2.05mm thinkness for $177.99


Obviously I would love for it to be the cheaper one, but I dont wanna put the wrong one in. If anyone knows which one it is, that would be great. Thanks in advance.

Do the thermostat first, if that doesn't fix the problem its the head gasket.

I had a similar problem, it was the thermostat.

From my experiance of head gaskets is that the 1.75mm one would be for normal replacment and the 2.05mm one would be for when you have had 0.3mm skimed off the head.

Do the thermostat first, if that doesn't fix the problem its the head gasket.

I had a similar problem, it was the thermostat.

although i agree with you, i did take out the thermostat and i tested it in boiling water. it opened just fine. despite that fact, i bought a new thermostat anyway for piece of mind, as well as a new water pump. but i think i might end up doing a head gasket and i just wanted to see which one i needed.

Unless you have a really bad head or head gasket problem, in which case you'd have other symptoms, a compression test probably won't tell you much. The most common problem is a small head gasket leak that is pumping air into the cooling system. That can cause overpressure of the cooling system and venting of coolant and/or cause overheating from a lack of circulation (the pump can't pump air). A single overheat "into the red" has been known to cause this and with a history of more than one overheat the chances of a head or head gasket problem are very high.

A simple test for this condition is to fully bleed the system and then re-bleed after a bit of driving (don't allow the engine to overheat). If there's a significant release of air on that or subsequent bleeds the head or gasket is suspect. A shop test for this condition is pressurize each cylinder with 150-180psi for several minutes while monitoring cooling system pressure with a sensitive gauge. A negative result on a cold engine requires the test to be repeated on a hot engine.

Also when the head is off id send it out and have everything checked