Author Topic: changing thermostat, a few questions. (Read 5080 times)

Twenty · « **on:** October 04, 2011, 07:11:39 AM »

Hi All

just changing the thermostat in my e30 and need a quick hand.

how do you remove the cam position sensor that crosses over the front of the thermostat cover? i have the thermostat out but i can see this getting in the way trying to reassemble the thermostat.

also how clean do you have to get the block mounting surface for the thermostat cover? i have it pretty clean (all previous gasket removed) and i think it will seal good with the instant gasket on there as well. just want to make sure it doesn't need to be spotless to seal.

thanks
glenn

monty23psk · « **Reply #1 on:** October 05, 2011, 12:01:36 PM »

regarding sensor, remove bolt with allen wrench, then wiggle/spin sensor out.

The housing should be clean. The trick is when installing the new gasket, using a little sealant to hold it in place and make sure to cut gasket, where there is a slit between the opening. THis might have gunk in it but is needed for the bleeding to let air through.

DesktopDave · « **Reply #2 on:** October 05, 2011, 01:32:46 PM »

+1...just remove that little hex head bolt, it's 5mm IIRC. The sensor might need a little twist to get it out, it's a tight fit. It's not fastened any other way. Don't pry it out. Also don't flex the wire too much if you can avoid it.

I'd strongly suggest replacing the cheap o-ring seal too, the cam sensor is a messy and common oil leak. Should look like an o-ring, not a square section gasket.

Monty has the right idea...or you can also install the paper gasket with no sealant. It'll stay in place while you tighten in up. I make sure that I check all those bolts twice over too, the housing can loosen up if one bolt really gets torqued down. I can't recall proper torque, it's not too much since it's secured in aluminum. Something like 20-25 lb-ft.

You don't want that little groove plugged up...it's the bleed passage for the thermostat. Bleeding the system is a complete PITA if that gets clogged up.

ironpaws · « **Reply #3 on:** October 10, 2011, 12:16:35 AM »

I bought my E30 318i five yrs back,FIRST thing I did was get rid
of the thermostat. The housing is touchy as can be about leaking,
so its just a matter of clean surfaces.
I replaced it with the OEM one which is available from several good
online parts houses.

I used the Permatex brown/black snot they use in FAA shops.
Its disgusting,stinks,sticks to your skin for days,and works without
fail.
Its available in those little fat bottles with a built in brush,I just forget
the specific name. Geez,and Ive used it for twenty yrs.
The great thing about these motors is how well they respond to
responsible and careful work. I am always amazed at how well
designed they are,how durable.
Just listen to particular warnings about the flaws they all have and
tend to them.
Use the highest quality parts and BMW antifreeze.
Oh,and GET a Bentley manual.

Twenty · « **Reply #4 on:** October 10, 2011, 05:47:46 AM »

thanks for the help, now i have my parts i can see a knick in the gasket, but i can't see if this is meant to line up with anything on the block, i take it there is something on the thermostat it should line up with?

also i didn't get a gasket with my water pump, and i can't see any part number on bmwfans for a water pump gasket. i take all i need is some instant gasket stuff for the water pump?

cheers

DesktopDave · « **Reply #5 on:** October 10, 2011, 07:26:21 AM »

The notch isn't designed to line up with anything. I thought the pump had an o-ring? Not sure, haven't changed mine yet.

Twenty · « **Reply #6 on:** October 21, 2011, 08:04:03 AM »

yeah it has an oring, didn't think of that, just though i needed a gasket to seat the pump to the block but the oring will do it.

There is a bit of surface corosion in the bore where the water pump going from water sitting doing nothing. Am i best just using a little wire brush to clear it out? and then bolt the new water pump in.

DesktopDave · « **Reply #7 on:** October 21, 2011, 08:56:25 AM »

Yep, keep her clean!

I'd use a brass wire detailing brush or a scraper/blade/knife to clean up aluminum instead of a wire brush...bits of leftover steel wire will rust.

Twenty · « **Reply #8 on:** November 26, 2011, 11:04:15 PM »

after it leaking the first time around, pulling out the thermostat reseating it and bolting it up, to hear a creaking noise.....

now the cover is cracked, pain in ass. Well in for another order from bma for another gasket and a new cover.....

anyone know if i did anything wrong or just got unlucky?

DesktopDave · « **Reply #9 on:** November 27, 2011, 09:43:02 AM »

Looks like the silicone make-a-gasket dried up on the bottom before it was torqued down. If that's what happened the housing gets cocked and torquing the upper bolts will crack the housing pretty easily. Might also be a casting flaw, that's pretty thin aluminum.

Mine needed a lot of cleaning & scraping when I swapped it this year, but the stock gasket made it easy to re-install.

I'd strongly recommend the stock paper gasket installed dry, no sealant at all. IIRC the BMW OEM part has a silicone bead already, they seal very well. Others have recommended aircraft-grade non-curing gasket sealer. Just make sure that bleeder channel stays clear.

Ryann · « **Reply #10 on:** November 27, 2011, 07:07:29 PM »

Looks to me like you tightened the housing down on the lip of the thermostat. It can be tough to get the thermostat to stay in its countersink while installing the housing over it. I've found that the cam sensor is a lot easier to deal with if you pull the crank sensor out as well. It gives you a lot more slack to work with without risking damage to the wiring and plastic loom brackets.

Twenty · « **Reply #11 on:** May 05, 2012, 03:05:27 AM »

geez this thermostat is the gift that keeps on giving....

the last one as mentioned previously with the cracked housing didn't seem to sit in its recess maybe causing the house to crack when nipped up.

so when i moved house i just ripped the thermostat out and drove without one. the engine still got noticably hot by the time i got to my destination.

thought it was about time i got the car on the road again, so a new thermastat and coolant and we should be good. or so i thought.

this time i purchased the OEM bmw item (Behr) hoping it should fit better.....wrong.....

you can see the o-ring under the lip of the thermostat here no sitting flush with the block and it isn't even resting on the o-ring. Its as if the thermostat is too round for the block and it sits proud.

does anyone else get this when replacing there thermostat's?

cheers
20

monko141 · « **Reply #12 on:** May 05, 2012, 09:14:55 AM »

Would probably help if you put the t-stat in correctly.
http://bmwfans.info/parts/catalog/E30/2-doors/USA/318is-M42/LHD/M/1991/february/browse/engine/waterpump_thermostat/

Twenty · « **Reply #13 on:** May 05, 2012, 05:31:36 PM »

geez....i have to learn to stop trusting my memory...

Thanks Monko