M30 Coolant Pump Replacement

[Mitch90535im]

Getting ready to do a water pump replacement on my '90 M30. Any tips or advice?

Should I use some form of Permetex type sealant in addition to the gasket that came witht he new pump?

[anonymous1]

Getting ready to do a water pump replacement on my '90 M30. Any tips or advice?

Should I use some form of Permetex type sealant in addition to the gasket that came witht he new pump?

Hi,

Excellent write-up here. Think you should find all the information you need... http://www.bimmernut.com/forum/showthread.php?t=37409&highlight=water+pump

Would recommend if you suspect the thermostat to be faulty to change this at the same time, save having to drain the system again.

HTH :D

[Rus]

No sealant is needed on the paper gasket. Its a little tricky to install since a lot of the time it comes all curled up in the pump box. I usually slide two of the mounting bolts into the pump and then hook the gasket on them. With a little patience, you can get the pump in pretty easily. Clean up the pump bolts so they don't corrode or damage the threads. Don't use a wrench to tighten the fan, just spin it on and it'll be a-ok.

+1 on the thermostat. Change it unless its new. Also, take a good look at the spigots on the t-stat housing. Mine got very crusty and nasty after nearly 19 years and my hoses started leaking at those connections. I ended up completely removing the thermostat housing from the block and cleaning the heck out of the spigots...no more leaks. Definitely something to look at if you're messing around in that area.

If you're not familiar with bleeding the M30 cooling system, you may run into minor issues. I normally drill a hole in the arrow stamping on the thermostat. Supposedly that helps get air out of the system. Bleed the car on a level surface or with the front slightly lower than the back. Fill the system with engine off and squeeze any hoses you can get your hands on to force air out of the bleed bolt on the t-stat housing and out through the reservoir on the firewall. Start the engine and keep squeezing those hoses once coolant starts circulating through the radiator. Keep an eye on the return line to the reservoir. There should be a steady stream of coolant pouring into the reservoir neck when there is no more air in the radiator.

HTH

[Mitch90535im]

"If you're not familiar with bleeding the M30 cooling system, you may run into minor issues."

Thanks Rus. That gets the prize for understatement of the year. I've had my e34 since 2001 so I've bled it (or attempted to) more times times than I care to remember.

Anyway, I noticed you recommended doing it nose down, whereas I've been doing it nose up. I might try nose down this time to see if it bleeds any better.

Knock on wood, but since 2001 the only unscheduled repairs I've done have been a radiator replacement, starter, and now the water pump. Not bad.

[Tiger]

Gasket sealant makes it easier to install water pump... you only put it on one side to the water pump. It merely helps the gasket stay on the waterpump until you start putting in the bolts.

[Mitch90535im]

Well, this one isn't going very well. Not one, but two water pump bolt heads rung off and a water water pump that will not release itself from one of the two remaining bolt shafts.

I've soaked it good with liquid wrench hoping to break the pump free tomorrow and then I'll soak the two remaining studs and try to remove them with a good pair of vise grips.

I wonder why my new pump came with only 3 new bolts instead of 6, because none of the 4 remaining intact bolts appear to be in very good condition.

Beginning to think I might have to take a chisel to the remaining threads around this frozen bolt to break the old pump housing away and expose the shaft of the bolt.

I'm kinda paranoid of damaging the block.

[e34.535i.sport]

I've soaked it good with liquid wrench hoping to break the pump free tomorrow and then I'll soak the two remaining studs and try to remove them with a good pair of vise grips.

A good tip for removing those studs: Get two nuts that will wind on to the stud and wind them on one after the other. Then use a spanner or whatever you can to back the 'first' nut off and the stud will come with it. Bish bash bosh... :D

Don't despair, we've all been there! You'll come out of it with a good sense of achievement!

If I were you I would replace hoses, thermo and waterpump all at the same time as it's just annoying when they start to go seperately. Trust me on that one ;) Good luck, keep us informed!

[Mitch90535im]

Excellent tip (on using the two nuts), thanks.

[e34.535i.sport]

"Excellent tip on using the two nuts"

So many jokes in my mind right now... :D

[Rus]

"If you're not familiar with bleeding the M30 cooling system, you may run into minor issues."

Thanks Rus. That gets the prize for understatement of the year. I've had my e34 since 2001 so I've bled it (or attempted to) more times times than I care to remember.

Anyway, I noticed you recommended doing it nose down, whereas I've been doing it nose up. I might try nose down this time to see if it bleeds any better.

Knock on wood, but since 2001 the only unscheduled repairs I've done have been a radiator replacement, starter, and now the water pump. Not bad.

To be honest, I've never had that much trouble bleeding my M30. When I tried it in a nose-up position, the system wouldn't fill with coolant properly. More often than not, I bleed in as close to horizontal position as possible.

Sorry to hear about your bolt troubles. Those bolts always seem to get nice and rusty.

[e34.535i.sport]

To be honest, I've never had that much trouble bleeding my M30.

Same here... We must be the 'chosen ones'!

[Mitch90535im]

Still can't seem to remove the pump from the block. Appears to be coroded on the smooth shaft of just one of the two bolts that broke. Looking for ideas on how to free it?

I had considered taking a hammer and chisle and cracking the pump housing around the stuck bolt or possibly drilling a couple of small pilot holes to try to get more Liquid Wrench into the bolt shaft to see if it will loosen it up.

I'm paranoid that I will damage the block prying on it because I have managed to do that on a Honda in the past.

Is the M30 block aluminum or steel?

[e34.535i.sport]

Still can't seem to remove the pump from the block. Appears to be coroded on the smooth shaft of just one of the two bolts that broke. Looking for ideas on how to free it?

I had considered taking a hammer and chisle and cracking the pump housing around the stuck bolt or possibly drilling a couple of small pilot holes to try to get more Liquid Wrench into the bolt shaft to see if it will loosen it up.

I'm paranoid that I will damage the block prying on it because I have managed to do that on a Honda in the past.

Is the M30 block aluminum or steel?

As far as I'm aware it's a steel block. In fact I'm pretty sure. I know mine didn't just fall off, it took a little pursuasion... I just gave it a few taps with a small hammer but I had all the bolts out luckily enough.

My memory's not serving here but I think the situation your in is most of the bolts are out, with a couple left in headless because they broke... Did you try the 'two nut' thing? That should get rid of the bolt problem at least. Give the pump a little knock with a hammer to loosen it up... You shouldn't damage anything unless you go crazy. Good luck, I'm all on edge here for you LOL! :D

[Rus]

I can't imagine how the pump could become so attached to a bolt. Last time I replaced my pump (~2 months ago) the bolts weren't exactly an exact fit in the holes of the pump. Verify that you got all the bolts and get yourself a small hammer for persuasion. My guess is that the gasket is pretty well caked onto the mating surfaces or someone used sealant before you got your hands on it.

e34.535i.sport,
He might not be able to get two nuts on the bolt if the head broke off flush with the pump housing.

[e34.535i.sport]

e34.535i.sport,
He might not be able to get two nuts on the bolt if the head broke off flush with the pump housing.

Sorry you're totally right... Getting ahead of myself there. Just hammer it, slide it off and then use the two nuts LOL! :D

+1 on the gasket... Nothing to worry about.

[whiskychaser]

If I understand correctly, the pump is stuck on the 'shank' of the bolts? That can happen if you get moisture/air in there. Instead of rust you end up with a horrible oxidisation which fuses the bolt to the surrounding part. If thats the case, I'd suggest you use shock treatment-dont be tempted to force a screwdriver between the pump flange and the block or you may score the block. Drive the pump away from the block from every direction you can using a piece of wood and a mallet/hammer.

[Mitch90535im]

If I understand correctly, the pump is stuck on the 'shank' of the bolts? That can happen if you get moisture/air in there. Instead of rust you end up with a horrible oxidisation which fuses the bolt to the surrounding part. If thats the case, I'd suggest you use shock treatment-dont be tempted to force a screwdriver between the pump flange and the block or you may score the block. Drive the pump away from the block from every direction you can using a piece of wood and a mallet/hammer.

Yes that's my situation. The pump appears to be "very firmly" attached to the shank of one of the two bolts that have broken. Not a lot of room for hammering from back toward front to free the pump from the block. Don't want to pry although I have used a very thin blade putty knife to slid between pump and block to get rid of any gasket that might be holding it. I believe it is just the oxidation of that one bolt still holding the pump as you suggested.

Been at the cabin all weekend so I'll try it again this evening when we get home to see if the Liquid Wrench and WD-40 that we've saturated it with have helped. I'm also tempted to try heat like from a paint stripper that the wifey has. The damn thing's coming off one way or the other this week.

Then I've got to get the two broken bolts out of the block at which time I'll either try the 2-nut approach or just soaking them good in Liquid Wrench and using vise grips to grab and turn the shaft.

[whiskychaser]

If you have some bolts out already you will be able to tell if there is enough thread to do the 'two nut' trick. My guess is there wont be but the remains of the bolts should come out easy enough with mole grips. If it were me doing the job, the bolts would of course break off flush with the block. The rad would then probably be in the way so I couldnt get the drill in...which is why I have one of these in my tool box: