MyE28.com

Hey guys i just noticed today that i had very low coolant. There was barely any in the tank.(I just filled it a few days ago) This has been going on for a while now but i really couldn't get to it. I finnaly tried to check it out today. I looked at the thermostat housing today and noticed all my nice blue BMW coolant seeping/dried up on the part of the housing that seperates(where the thermostat goes). I then looked at the hose that comes off of the bottom of the housing. That had dried coolant all around it too. Now as far as the housing goes, i reused the old thermostat gasket last time i changed the thermostat. Is this why i have coolant all over it? Plus my hoses look like they need to be replaced and i don't have any actual record of them being replaced so im doing that too. I've been into the housing before but its been a while. Theres no other gasket than besides the thermosat one right? The thing that is upsetting me is all my coolant is being wasted. Normally one wouldn't fret over this but that damn BMW coolant is $18 a gallon. !@#$ Thanks Guys

YOU ALWAYS REPLACE THE GASKET!!!!!! the o ring should be replaced too. The gasket is definiley your problem change them hoses when you get a chance. Remember if it has a gasket, no matter what replace that $hit.

I have been having exactly the same problem. My coolant is the green stuff so it didn't bother me as much. I also reused the gasket when I tested my thermo and replaced the radiator 2 yrs ago. It has used less than a gallon of coolant in 2 years, but a couple weeks ago it started leaking out of the radiator-expansion tank hose coupling... and then mysteriously stopped. I'd appreciate any additional comments, thanks all.

[QUOTE="smackmybutter535i"]YOU ALWAYS REPLACE THE GASKET!!!!!! the o ring should be replaced too. The gasket is definiley your problem change them hoses when you get a chance. Remember if it has a gasket, no matter what replace that $hit.[/QUOTE]

So what your saying is that there IS another gasket to replace besides the thermostat o-ring. Where the hell is it? I didn't see one online. Do i have to go to the dealer to get em?

Here's the link to the thermostat o ring and gasket.
Check the thermostat housing for excessive corrosion where the hoses attach. At least clean up any looose scale before reassemling.
If the corrosion is real bad I would get new housings.

http://www.realoem.com/bmw/partgrp.do?m ... g=11&fg=35

Ummmm.....No gasket listed there. O-ring.

[QUOTE="Nick C."]Hey guys i just noticed today that i had very low coolant. There was barely any in the tank.(I just filled it a few days ago) This has been going on for a while now but i really couldn't get to it. I finnaly tried to check it out today. I looked at the thermostat housing today and noticed all my nice blue BMW coolant seeping/dried up on the part of the housing that seperates(where the thermostat goes). I then looked at the hose that comes off of the bottom of the housing. That had dried coolant all around it too. Now as far as the housing goes, i reused the old thermostat gasket last time i changed the thermostat. Is this why i have coolant all over it? Plus my hoses look like they need to be replaced and i don't have any actual record of them being replaced so im doing that too. I've been into the housing before but its been a while. Theres no other gasket than besides the thermosat one right? The thing that is upsetting me is all my coolant is being wasted. Normally one wouldn't fret over this but that damn BMW coolant is $18 a gallon. !@#$ Thanks Guys[/QUOTE]

BMW coolant?~0 Try Prestone, it's less than half that.

Further, as someone else stated, a fresh gasket comes with the T-stat and it's ALWAYS to be used. Also, hoses deteriorate fromt he inside out, so yes, definitely replace them, particularly any that are bulging near a clampl



[Edit by fastpat on [TIME]1108097986[/TIME]]

Have to disagree with the gasket.

One of the first thing I did to my car was to install a thermostat, it didnt have one. I put the o-ring on the thermo and put in the gasket.

Now when I took a look at the engine out of the car I noticed that I could stick my finger in the hose nipple and wobble the thermo back and forth. This was because the added thickness of the gasket didnt allow the 2 halfs of the housing to pinch and seal with the o-ring.

If you look at older M30's, i.e. E12 528i, you see the gasket and o-ring, but any E28 M30 uses just the o-ring. If your housing wasnt designed for the gasket you will have leak by.

On my 533i, it took three tries to get the leakage stopped (hopefully not a statement on my ability). Turns out there was buildup at the base of the mounting studs (not much) that combined with rust in the channels for the stud in the housing, prevented the housing from being completely tightened down. After cleaning the base of the studs, chasing the threads, drilling the rust out of the stud channels in the housing, and oversize drilling the channels (1/64 deep) where the faces go together, no more problems when put back together.

there is no gasket.. ETK doesnt show one for e28's and the dealer said there wasnt one when i replaced the thermostat in my 535i last year.. one came of the car when i took it off and i didnt put it back.. i had leaks because of this. I think my housing cover was warped a little or something. I made a gasket to put back in there which stopped my leak.

There is a gasket when you buy a complete headgasket kit, it comes with one that goes between the aluminum housing and the cap. The o-ring just seals the t-stat inside the housing, but not coolant to the outside of the housing. Mine leaks from there, I will probably fix it tomorrow.
The best product to seal engines with is what Mercedes Benz uses as an entine gasket, its a black silicone based sealant that is amazing at sealing gaskets. It supposed to be used by itslef, but when mated with a gasket it seals perfectly everytime.
I am a BMW Dealer Tech and we use this stuff whenever possible to make sure there are no leaks in the oil/cooling systems.
HTH.

[QUOTE="Dave_in_VA"]Have to disagree with the gasket.

One of the first thing I did to my car was to install a thermostat, it didnt have one. I put the o-ring on the thermo and put in the gasket.

Now when I took a look at the engine out of the car I noticed that I could stick my finger in the hose nipple and wobble the thermo back and forth. This was because the added thickness of the gasket didnt allow the 2 halfs of the housing to pinch and seal with the o-ring.

If you look at older M30's, i.e. E12 528i, you see the gasket and o-ring, but any E28 M30 uses just the o-ring. If your housing wasnt designed for the gasket you will have leak by.[/QUOTE]

Sorry for the confusion I caused, when I said gasket I meant the O-ring gasket, not a paper gasket.. It's the O-ring that's always renewed.

It's been quite a while since I replaced my waterpump and thermostat so I don't recall if I used a gasket or not. The link to the online ETK I posted above was for my 88 535i's VIN and it does show the gasket in the third picture down.
I do know I use a gasket for my e12's.
Bob

[QUOTE="M3 Ryan"]There is a gasket when you buy a complete headgasket kit, it comes with one that goes between the aluminum housing and the cap. The o-ring just seals the t-stat inside the housing, but not coolant to the outside of the housing. Mine leaks from there, I will probably fix it tomorrow.
The best product to seal engines with is what Mercedes Benz uses as an entine gasket, its a black silicone based sealant that is amazing at sealing gaskets. It supposed to be used by itslef, but when mated with a gasket it seals perfectly everytime.
I am a BMW Dealer Tech and we use this stuff whenever possible to make sure there are no leaks in the oil/cooling systems.
HTH.[/QUOTE]

No, as you can see from the parts manual photo, which shows the correct installation sequence:



The O-ring (no. 8) does indeed seal the T-Stat housing (no. 6) from leaking coolant. The T-stat (no. 9) goes in first, then the O-ring, then the housing is bolted down.

Pat, I saw that but what is the gasket that shows in the next picture down for.
BTW did you get my email?
I have an OBC if you still need it.
Bob


[Edit by Bob in San Jose on [TIME]1108276920[/TIME]]

[QUOTE="Bob in San Jose"]Pat, I saw that but what is the gasket that shows in the next picture down for.
BTW did you get my email?
I have an OBC if you still need it.
Bob

[Edit by Bob in San Jose on [TIME]1108276920[/TIME]][/QUOTE]

Ah, that gasket goes between the cylinder head and what BMW calls the T-stat housing (where all the sensors are screwed in). Most people, including me, refer to the T-stat cover as the housing since that 's what we remove to install the T-stat, and most US car makers have always call it on their engines.

And, no, I didn't get your email about the OBC yet, try fastpat@comcast.net .



[Edit by fastpat on [TIME]1108277540[/TIME]]

Have to disagree Pat. The picture shows it on the TStat side not the side that goes to the head. I went out to the garage and checked to see if that was correct and it is. I also think I do see a gasket there, although I didn't pull the TStat cover to confirm.

Bob

[QUOTE="Bob in San Jose"]Have to disagree Pat. The picture shows it on the TStat side not the side that goes to the head. I went out to the garage and checked to see if that was correct and it is. I also think I do see a gasket there, although I didn't pull the TStat cover to confirm.

Bob[/QUOTE]



Yeah, I know it looks a bit like the gasket (no. 2) goes between the T-stat cover and the T-stat housing (no. 1), but trust me, it doesn't. As you can see, it's the wrong shape to be near the T-stat, and precisely the correct shape to go between the head and housing. Here's the head, the location of the water passage near the front of the engine matched that gasket shape.


A paper gasket would act to prevent clamping the O-ring tightly enough to seal.

Interestingly, I just had a similar issue with my M20 engine, it that I put the O-ring in first, then the T-stat (I shoulda' paid more attention(@) ). It leaked. Switched it around, now it's sealed fine.

I see, that is correct, that looks like the gasket that goes between the head and the TStat housing. I'll have to pull my housing and confirm if I have a gasket that goes between the TStat housing and the TSat cover or not.
If there is one it's been on a long time and never leaked or given me any other problems.
I just looked in the Bentley and it claims there is a gasket for the M30 engine but not the M20. Page 10.9
I'm confused.

[Edit by Bob in San Jose on [TIME]1108279913[/TIME]]


[Edit by Bob in San Jose on [TIME]1108280700[/TIME]]

[QUOTE="Bob in San Jose"]I see, that is correct. I'll have to pull my housing and confirm if I have a gasket there or not.
If there is one it's been on a long time and never leaked or given me any other problems.
I just looked in the Bentley and it claims there is a gasket for the M30 engine but not the M20. Page 10.9
I'm cofused.

[Edit by Bob in San Jose on [TIME]1108279913[/TIME]][/QUOTE]

I checked the 533i and the parts for it are the same as the one's in the photos I posted above, but when I went to the '79 e12 528i, this is what was shown:


Plainly, a paper gasket was used at one time, I don't know when it was discontinued.

[QUOTE="smackmybutter535i"]YOU ALWAYS REPLACE THE GASKET!!!!!! the o ring should be replaced too. The gasket is definiley your problem change them hoses when you get a chance. Remember if it has a gasket, no matter what replace that $hit.[/QUOTE]

[QUOTE="Nick C."]So what your saying is that there IS another gasket to replace besides the thermostat o-ring. Where the hell is it? I didn't see one online. Do i have to go to the dealer to get em?[/QUOTE]

It usually comes with the thermostat When I bought mine I was in a pinch and couldn't get to forign auto. So I bought it at ADvance auto parts. and they had both in stock for cheap!!

Ok. I went to BMW bought the thermostat and this is what they had. (they didn't give it to me i had to pay $3 for this gasket. similar to the one BavAuto send with ther thermostat)



so is this what your talking about that you had to get from advanced auto parts?

That is just the O-Ring for the t-stat, and it should have been given to you in the box with the t-stat as its part of it.
I just looked at my spare t-stat housing and it has a gasket on it between the housing the the cover that is removed for t-stat changing. I also looked at the one on my car and it has a paper gasket in there ass swell... interesting why the ETK doesn't show it, but its provided in a headgasket kit and both of my housings have one already...

85 535i
Recently changed my thermostat. I think that this thermostat was some German make but cannot remember the manufacture right now. Thermostat came with a paper gasket and o-ring.

There was a paper gasket on my car and the o-ring.

There was a significant amount of pitting and poor surface around the o-ring sealing surfaces.

It took two tries to get things to seal even with the paper gasket. I ended up gooping it up rather inelegantly with a Teflon product to get it to seal.

Broke a bolt head off when removing the thermostat cover and I had to remove the shank with pliers. I think it was 6mm x 70mm producing a 10mm head.

Could BMW have added the gasket later via a tech bulletin or something to help with corrosion/sealing issues at maintenance and repairs?

P.S. that site is a great rescource.
http://www.realoem.com/bmw/partgrp.do?m ... 0TJscMgUTV

[QUOTE="Threeshifter"]85 535i
Recently changed my thermostat. I think that this thermostat was some German make but cannot remember the manufacture right now. Thermostat came with a paper gasket and o-ring.

There was a paper gasket on my car and the o-ring.

There was a significant amount of pitting and poor surface around the o-ring sealing surfaces.

It took two tries to get things to seal even with the paper gasket. I ended up gooping it up rather inelegantly with a Teflon product to get it to seal.

Broke a bolt head off when removing the thermostat cover and I had to remove the shank with pliers. I think it was 6mm x 70mm producing a 10mm head.

Could BMW have added the gasket later via a tech bulletin or something to help with corrosion/sealing issues at maintenance and repairs?

P.S. that site is a great rescource.
http://www.realoem.com/bmw/ [/QUOTE]

I just pulled the T-stat and cover off my M30B35 engine, it did not have a paper gasket in it, just had the O-ring. In another development, the T-stat cover (using BMW's nomenclature) that came off the engine is part number 268 651, while the online ETK says the part number for all late e28, all e32's, and al e34's with the M30 engine is 268 650. I wonder what changed?

Here's the T-stat cover with the T-stat still "attached" by the O-ring, there's never been a paper gasket on this housing, nor one on the T-stat housing proper.


The T-stat temp rating, the number 1200 is obscured by the shadow. I don't know what that's for.


A side view of the T-stat cover with T-stat attached.


The O-ring has been flattened on the side facing the cover, still round on the side facing the thermostat.


The thermostat cover part number, inside.




[Edit by fastpat on [TIME]1108366551[/TIME]]