Thermostat info

[karl1171]

Just been searching the forum: My 525(M50 1991) takes a lot longer to reach mid way on the temp gauge then my 520did, I'm suspecting the thermostat. I bought a replacement but I'm a bit concerned.

Im Assuming the thermostat is located at the front of the engine behind the part where the top and bottom radiator hoses are attatched. however there's no paper gasket in the kit, only rubber washers.

Is this the right location and do I need a paper gasket?

[winfred]

that's where it is and it depends in what type of housing your car came with, some use a fiber gasket and a o-ring, others use two o-rings, plastic housings and aftermarket aluminum units use two o-rings, factory aluminum use one o-ring and a gasket

[Evan]

I'm thinking of doing my thermostat today. My engine is the M60. I have the part in hand and I've been looking for as much info as possible as i don't quite have the guts to start the job!

Anything I should be prepared for?

[winfred]

v8s are essy, if you have a plastic housing get a new one because they suck worse then the 6 cylinder units for cracking, they pretty much go without problem


I'm thinking of doing my thermostat today. My engine is the M60. I have the part in hand and I've been looking for as much info as possible as i don't quite have the guts to start the job!

Anything I should be prepared for?

[Evan]

Thanks Winfred! Has anyone ever done one of these?

[632 Regal]

I did. One of the bolts is a challange to get at and might frustrate you but other than that its pretty straight forward. Be very careful that you dont pull the tube out that goes to the back of the engine while removing the pump or you may develop a leak at the rear that will require intake removal to get in to replace the O ring.
Thanks Winfred! Has anyone ever done one of these?

[Evan]

Thanks, Brian. I'm gonna need to do some more homework because I'm clueless on this one... I've done more complicated things to cars but I need to be a little more cautious here because this is my ddaily driver.

[Trevor]

Just did the thermostat on my 535iA
Use caution with replacing, esp on the torques. Borke of 1 bolt with alittle too much over tighhtening...
On the 535iA there is a choice between a 80degreeC and 90 degreeC thermostat. I use the 0degree as I live in ahot climate.
Thermostat comes with rubber ring.
Only use BMW coolant - need it for pump lubrication.

[karl1171]

I'm not entirely sure if this is worth doing anyway, the engine does reach normal temperature, I'm thinking it may have took a little longer because its been cold here over the last week or two.

[granit_silber]

I'm not entirely sure if this is worth doing anyway, the engine does reach normal temperature, I'm thinking it may have took a little longer because its been cold here over the last week or two.
Karl,
When was the last time the T-stat was replaced? As Jeff regularly points out, on these cars t-stats, water pumps, and hoses are consumables.

Changing the stat on the M50 is really easy, and this is from a guy who didn't know how to change his oil until earlier this year.

Take a look at the housing on the block. If it's aluminum (and OEM) it will require a paper gasket. They're a pain in the butt to scrape off and you have to be sure you get both the block and the housing super smooth.
After two paper gaskets, I chose to purchase the composite housing from a local stealer (approx $40). The newer housing uses the o-ring for the t-stat and a rubber gasket for the second opening. It was a breeze to install and I was up and running in less than an hour.
The paper gasket will set you back about $10 from a stealer, the rubber gakset around $8.

Here's my advice.....
Remove the housing and if it uses a paper gasket put it off to the side.
Buy the composite housing new (w/gaskets)
Scrape the block nice and clean.
Install new housing and t-stat per Bentley
Plan on replacing the housing when you replace the t-stat and pump next.
Next time you're looking for something to do, scrape the gasket off the old housing. :)

This repair isn't difficult, just make sure you have either
1) all of the right parts and tools available or
2) transportation should the need arise

good luck,
-ashley

[tibbe]

Thanks for the tips and tricks.
Will change my t-stat tomorrow, temps doesn't leave the blue field and it's a bit chilly outside -21C appr. -10F. .. and not so warm inside.
Have a -93 520iAT w/o AC.

A Q. do I need to take the fan out, or just dismount the housing.

/tibbe Lulea Sweden

[Akhil]

I have the same engine M50. When I did my t-stat I took fan out. It will ve lot easier if you take fan out. You need good amount of space to sand the block surface before you put new gasket, if its paper gasket. Also, I would say use litter bit of T-stat/water pump sealant on both housing surface, skick the gasket and apply little bit of same sealant on top of gasket. I first did it without sealant and it was leaking. I had to drain coolant and take it out again. Then used new gasket with sealant and its fine now. You can find that sealant for $0.99 in any auto store.

Good Luck

Akhil

[tibbe]

Hi Akhil.
Thanks for the advise about sealent, will do that.
Any special tricks to take out the fan?

/Tibbe

[Akhil]

I used adjestable wrench ($ 15 from walmart), its big num (32mm) and I couldn't find wrench that big in any store. Be careful about the nut, it is reverse threaded, mean to open it you will have to rorate clock wise. If you do anti-clockwise you might break the thread.

Good luck

Akhil

[tibbe]

Thanks a lot Akhil.

We got nearly dissapointed, no challange went so fast we didn't have time to take a beer.
Did it outside in appr. 20min, only -5C.

As you wrote a big adjustable and a hammer. Took out the fancover mounted to the cooler with the fan. And then the thermostathouse 4 + 1 bolt.
Cleaned the surfaces, mounted thermostat ( 92C vs. the mounted 88C ) and gaskets. It's a composite housing. Filled up with wather and let it run warm to bleed the cooler.

A great change in interrior heating. Much more comfortable.

Off to the next wrenching task, have to look for something to renovate.

/Tibbe.

[Akhil]

You welcome tibbe,

Make sure you bleeded the system right and drive for few days with heater knobe to max. If you have radiator mounted expansion tank and need help in bleeding, let me know. I will give you a trick to bleed the system even without statring the car and without heating the coolant.

Akhil

[tibbe]

We tried to bleed it this way. Filled the heater mounted expansion tank and opended the bleeder. Refilled continiously while having a nice chat.
Then with the expansion tank filled and closed started the engine with the heater knob on max and opended the bleeder from time to time and keept the level in the expansion tank high until the thermostat opened. Then bleeded once more after a minute and stopped the engine. Had a coffe and refilled the expensiontank and then went for a 10 min drive home and bleeded once more at home.
Will continue to drive with heater knob on max even if it's a bit warm for some days and bleed/refill.

/tibbe

[Akhil]

I think that should be it. You have got all air out from the system.

Akhil

[nychappygolucky]

I was just wondering if someone could help me to locate the thermostat for my 95' 530i with close to 100K miles. Obviously I was not able to find one. Pictures would be quite helpful.

This is part of my attempts for resolving a coolant leak as someone in this forlum suggested to look into. I am crossing my fingers that thermostat is the cause of problem.

I thank in advance for your help!!!


v8s are essy, if you have a plastic housing get a new one because they suck worse then the 6 cylinder units for cracking, they pretty much go without problem

[Kalevera]

I was just wondering if someone could help me to locate the thermostat for my 95' 530i with close to 100K miles. Obviously I was not able to find one. Pictures would be quite helpful.

This is part of my attempts for resolving a coolant leak as someone in this forlum suggested to look into. I am crossing my fingers that thermostat is the cause of problem.

I thank in advance for your help!!!
Near the front leading edge of the engine, and below the throttle body and intake plumbing, you'll see two large (~ 1 inch dia) radiator hoses going to a housing, one from the left/one from the right. The assembly is the water pump/thermostat housing & cover. Each hose can be traced directly back to the radiator; the lower radiator hose (on the right side of the car) goes from the near-bottom of the radiator to the thermostat cover. The upper hose (on the left side of the car) runs from the top of the radiator to the water pump outlet.

On the early V8s, it's easy to overlook the heater valve, aux water pump and associated piping that are located by the driver's side firewall, below the expansion tank. The plastic side tanks on the radiator can also fail and slowly leak coolant, a leak that may only be apparent from under the car.

best, whit