Ackpffft! I may have killed it....

[jmc1590]

Here's the rundown:

Have been working on a '94 325i for a while now. PO stated that it had head gasket issues, because it was loosing coolant. I did find a damaged radiator, damaged radiator bottle cap, and stripped bleed screw while diagnosing the issues. Replaced all three, and it seemed to be running well. Took it on it's first distance run to work and back (~250mi round trip) yesterday. No cooling issues detected and it ran rather well. (At least the motor did. Suspension - another story...)

Thinking it's doing ok, I decide to take it to work again this morning. Smaller and lighter, it gets better gas mileage than my E39 528i. About 10 minutes down the road, I notice the temp guage starting to climb past center. Took about a mile to find a spot to turn around. By then, it's almost into the red. (No light.) Stop for a bit and limp back to the house. At this point, I've turned the heater on full to attempt to bleed some residual heat. Bad idea. Shortly, the cabin is filled with a heavy white coolant "fog" that has poured out of my vents! WTF!

Get it home. When running, I can see jets of steam shooting from near the water pump to under the intake manifold. It takes close to a gallon of liquid. As I introduce more coolant, the temp guage drops and centers up. Switch cars, go to work.

I'll be digging into what has actually happened. Ruptured coolant hose? Some other hose? I'll be draining the oil to see if I've gotten any contamination. I suspect I'll be pulling the radiator, so I can check what coolant is remaining for any oil. Then I'll put together some form of pressure tester to check the cooling system. Hopefully, no damage was done to the head. But you never know...


James

[mslevin]

You can rent a pressure tester from most auto parts stores. They don't always have the correct adapter, but its worth a shot. Best of luck!

[Eric93se]

After your long trip and the car cooled down, did you check the coolant level?

Most likely the head is damaged, do a compression check. Just so you know if it overheats at all, the head warps and can crack.

Whether it was damaged already or you did it in when you drove it and saw it was overheating (can't do that with these cars).

[jmc1590]

After the long trip, coolant level was right at the "kalt" mark, about 2" down from the neck.

I'm leaning towards gasket failure at either the water pump or thermostat housing. (Could be wishful thinking!)

If compression test or cooling system pressure tests show any indications, I'll pull the head. I'd rather not, but I'm comfortable with M52's so the M50 shouldn't be too difficult.

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[mnguyen84]

you should have towed it back. it would suck if a faulty hose turned into a warped head...or even worse....a warped block. you can check the headgasket by looking for coolant in the oil. also you can leave your radiator cap open, when your car is running. if the gasket is blown, then bubbles will keep coming out endlessly when the engine is warm.

[E36328Coupe]

Just so you know if it overheats at all, the head warps and can crack.

Can is not will though, they can be baked into the red, ran dry and driven and be fine.

[cbayles01]

Sounds like you had sufficient coolant etc. Only thing it could be is the line you saw steaming.

There is a rubber hose under the manifold that connects to the block with a clamp. I overheated that way also but its somewhat nice because was able to drive after waiting for the car to cool down. Getting the coolant in the cabin is definitely because that line was loose. I think turning on the heat is what you're supposed to do but haven't personally haven't done it. Pressure test might not reveal leak since its a rubber line. Not sure if old hose or not but would replace since rubber, definitely do know that the clamp was moved to leak the coolant.

[jmc1590]

I'm thinking it may, just may be ok afterwards. Drained the remaining coolant this weekend. No signs of oil. Draining the oil was on the list, but mission creep got the better of me. Flushed out the radiator, block & heater lines. No obstructions seen. Removed the thermostat & housing to find a mess of RTV! A lot of it remaining from various maintenance operations. With the amount of sillicon "crust" that was left in there, there is no way that could have been sealing properly.

Next steps are to pull the intake manifold and inspect all the vaccum and coolant lines under there. In the process, I think I'll try to do something about my peeling / flaking valve cover. I know it needs new gaskets, so while I'm there...) A major contributor to the coolant in the cabin is I've been running without the air shroud attached. (The sheet metal that issolates the engine bay from the blower motor.)

Last item - I've got evidence of some kind of copper based stop leak in the coolant. How does one clean in out of the system? (Repeated flushes? 1/2 a jug of simple clean in the radiator?)

Thanks!

James

[Nanniepoo]

Your commute is 250 miles? My God. Mine is less than 10 round trip.

[jmc1590]

Yeah.... 125 - 140 each way. Definitely need cruise control working! Not too terrible. Mostly Interstate and toll-roads.

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[Nanniepoo]

That's crazy just from the time commitment. I was in a van pool for a 50 mile commute each way, but with traffic it was about 2 hours round trip. And that was with me not driving, I could watch videos or sleep the whole time and I was still a bitter bitter man.

[LSxDreamer]

That's crazy just from the time commitment. I was in a van pool for a 50 mile commute each way, but with traffic it was about 2 hours round trip. And that was with me not driving, I could watch videos or sleep the whole time and I was still a bitter bitter man.

I've thought of taking those vanpools and nah, I'm okay.

[Nanniepoo]

I've thought of taking those vanpools and nah, I'm okay.

I'd recommend them honestly. 50% because it kept miles off my E36 and kept it from getting broke, and 50% because I slept both ways, meaning I only spent about 5 hours of my precious time at home in bed.

Honestly there were week long periods where I didn't drive. Rode my bike the 3 miles to/from the commuter lot

Sent from the dark side of the Moon

[cbayles01]

I'm thinking it may, just may be ok afterwards. Drained the remaining coolant this weekend. No signs of oil. Draining the oil was on the list, but mission creep got the better of me. Flushed out the radiator, block & heater lines. No obstructions seen. Removed the thermostat & housing to find a mess of RTV! A lot of it remaining from various maintenance operations. With the amount of sillicon "crust" that was left in there, there is no way that could have been sealing properly.

Next steps are to pull the intake manifold and inspect all the vaccum and coolant lines under there. In the process, I think I'll try to do something about my peeling / flaking valve cover. I know it needs new gaskets, so while I'm there...) A major contributor to the coolant in the cabin is I've been running without the air shroud attached. (The sheet metal that issolates the engine bay from the blower motor.)

Last item - I've got evidence of some kind of copper based stop leak in the coolant. How does one clean in out of the system? (Repeated flushes? 1/2 a jug of simple clean in the radiator?)

Thanks!

James

Might as well replace all those heater hoses that are back there behind the block while you have the manifold off. Replacing few plastics pieces back there would also will make your car almost hit less when it comes to overheating.

[jmc1590]

Update - Work schedule has been hectic of late, so it's do a little at a time, as I can. Today, I was able to pull the head. Good news, no signs of cracking! Head gasket has seen better days, but no obvious blow thru areas. After I get the head cleaned up, I'll check for warpage. (Straight edge and feeler gauges.)

What did surprise me was the valve damage in cylinder 4. Almost looks like a Phillips bit made its way inside! No obvious damage to the bores. So this may only cost me a valve!

I'll update as I get more info.

James

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[Eric93se]

Did you do a compression check before pulling the head?

On these cars the head gasket itself rarely fails, but the head warps and can crack (as previously mentioned).

No obvious steam cleaning of the valves, how about the piston tops?

[jmc1590]

Alas, no compression check before tearing it down. A number of things were going on, and it just didn't happen. The piston tops look normal (dirty-black) with no signs of damage. There was some light rust forming in the bores. I took some 5w30 and liberally applied. Then turned the engine over a few times. Rings did a nice job of removing excess (read most) oil in cylinders.

Head appears to check out. Using a straight edge diagonal across the head didn't allow a feeler gauge underneath. Likewise across and lengthwise. No cracks seen, but I'll hit it with some dye-penetrant from work to be sure.

Only real pain is the valves. My old Craftsman valve compressor, which does M20 heads great, just isn't up to an M50 head. Too much stuff in the way. Maybe if I pulled cam tray studs...

As it sits, I'm looking for a way to tear the head down the remainder of the way. Check the guides in the damaged cylinder and go from there.

- James

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[jmc1590]

Well, I've been able to makeshift a spring compressor. 3 exhaust valves removed. 3 exhaust valves bent. WTF!

Upon close inspection, it appears most of the exhaust valves have issues. One has a cracked face, a bunch aren't sitting "flat" on their seats. (Slightly off center and tilted.)

It's possible I bent the valves, but based on the others, I doubt it.

Looks like I may go searching for a head to pull at a nearby yard. That ($100) or $200 in new valves plus machine shop work.

- James

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[Eric93se]

With things torn down, its a good time to rebuild all the lifters. There are youtube videos on how to open them for cleaning.

[cbayles01]

With things torn down, its a good time to rebuild all the lifters. There are youtube videos on how to open them for cleaning.

Seconded on those lifters. Before I did an engine swap, I had the the lifter tick. Man that sound is embarrassing.

- - - Updated - - -

Well, I've been able to makeshift a spring compressor. 3 exhaust valves removed. 3 exhaust valves bent. WTF!

Upon close inspection, it appears most of the exhaust valves have issues. One has a cracked face, a bunch aren't sitting "flat" on their seats. (Slightly off center and tilted.)

It's possible I bent the valves, but based on the others, I doubt it.

Looks like I may go searching for a head to pull at a nearby yard. That ($100) or $200 in new valves plus machine shop work.

- James

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Hey at least all that stuff is getting dealt with now. Will be extremely dependable and smooth when finished

[jmo69]

My thoughts on the steam through the vents is leaking heater core.

[jmc1590]

While possible, I witnessed the steam coming from under the intake manifold, at the front of the engine. (Behind water pump area.)

The entry to the cabin was probably due to running without the firewall / vent cover installed.

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[jmc1590]

Update - Pulled all the valves. Found what I consider severe wear on one of the exhaust seats. Appears to be worn down to just one angle. Additionally, when a good valve is inserted, it sits .5mm lower than the rest. I'm not sure if it's salvageable. I'll be talking to a machine shop this week to see what they can do.

Posted one of the "bad" valves. Compression test &/or leak down would have led me to believe it had blown a head gasket, so I'm not upset at pulling the head.

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[jmc1590]

-update-
A 95 325is recently showed up in a pull yard near work. I figured, what the heck, it's worth a shot.

Spent about 3 hours yesterday pulling the head. Note - When the manuals suggest not doing this alone, they might be right! After everything was unbolted, trying to lift the head out of an elevated engine bay was rough! For what it's worth, the head can be removed with the cams still installed. They will need to be rotated to allow clearance to the head bolts. Be careful and don't force it! Piston interference is very possible.

Started cleaning and tearing down the head today. Mating surface looks promising. One of the cam journals (on the cam, not the head) is scored. As long as the bearing surface on the head & caps looks good, any issues with using another M50 cam? (Also, can you switch cam caps, or are those mated to each head?)

Next step is to pull the valves, check for guide wear, and install new seals. Perhaps a light lapping depending on how the seats look.

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[jc43089]

Keep the cam caps with the lifter tray, you could use your existing cam/tray/and caps.