Engine Temperature, Thermostat Replacement

[GoldenEagleFan]

E34, M50 1994 525i 155,000 miles

My engine temp gage needle just makes it over the first mark, never to the center, and seems to take ten minutes of running at highway speed to make it there. It has been 30F here so I am suspecting I should replace the thermostat. (One day here lately it was 50F and then the gage needle fell one width needle width short of center) As long as I have it apart, I was going to change the upper and lower radiator hoses. My questions are:

1) Should the other smaller diameter hoses also be replaced. I don't know when they were serviced last and am wondering if they are prone to failure.
2) If so, how do I get at the hose connection under the intake manifold. I can't find anything in the Bently manual.
3) I have an aluminum thermostat housing. I've seen on this site I need an o-ring and paper gasket. Any other insights/cautions...
4)Is it worth the $60 for the fan nut removel tool and pulley holder to get the fan assemblly off?

Thanks

[shogun]

I change my hoses on a regular basis before I run into trouble and the head might overheat with a blown hose somewhere in no-mans-land.
The fan nut removal tool is too expensive with 60 $. Just find a cheap tool in your local shop and grind it flat to fit.

[Akhil]

I user a long conbination wrench to open the fan nut. It need to be 2 size bigger than the bolt size. Put the round side of wrench in nut and hold long hadle againt the pull hub. You need extar levarage, then you can insert the wrench into a pipe. It worked for me. Hope it will help. Good luck.

Also, use paper gasket in t-stat housing, sand the block and housing suface clean and don't forget to user t-stat/water pump sealant on either side of gasket. I did without sealant and it was leanking. I had to do that all over agin with sealant.

Akhil

[632 Regal]

all hoses and belts are routine maintenance items, the tool you need to hold the fan when loosening the nut is...

[DanDombrowski]

Jeff,

I'm about to do a tstat replacement since my temp gage recently pegged itself in the blue region. I don't understand what you have to remove the fan for?

Now, about the special tool- do I need that if I have air tools? Or can I just hit it with the air ratchet and off it comes?

[Akhil]

There is no room for air tool. The only way to open the fan is to hold the pully with "SOMETHING" and turn 32mm fan nut clockwise with open-ended wrench or an adjustable wrench. That SOMETHING can be special tool or long screw driver or pry bar or long boxed-ended wrench, which ever you can get to hold the pully in place and not leting it turn when you turn fan nut. Hope this will help.


Good luck.
Akhil

[ryan roopnarine]

Jeff,

I'm about to do a tstat replacement since my temp gage recently pegged itself in the blue region. I don't understand what you have to remove the fan for?

Now, about the special tool- do I need that if I have air tools? Or can I just hit it with the air ratchet and off it comes?

dan, you don't need to remove the fan clutch to do a thermostat on the m50. you will, however, likely need to use 1/4 inch drive tools in the area (or combination wrenches), as there is no room if you don't remove it. you must also be careful. i have two broken thermostat housing bolts down there because i tried to remove it (with the clutch on) on the side of the road (the water pump was dead, i was taking out the thermo. just to be sure). the seal has lasted for many thousands of miles, but i'd rather have the bolts down there, if i had the luxury of taking it off at my home.

[DanDombrowski]

Thanks Ryan, thats what I thought.

I think I am going to remove the fan ahead of time though. Me being forever go-fast minded, I was planning on doing a fan-delete at the same time as the tstat. Seems as if many 325 and m3 guys have done so on the BF.c forums with no ill effect and a slight HP improvement. Seeing as I've been itching to get out to the track lately, and I don't like to go without some improvement in my car each time, I figured that wouldn't be a bad idea. I didn't want to state that upfront because I wanted an answer on the removal steps before hundreds of "thats not a good idea" posts.

I also have a bit of a rattle upfront I'm trying to track down, it would be good to at least run it for a few days without the fan to see if its an imbalance rattle or if its in the engine.

This of course is after the valve cover gasket job and tstat housing gasket on the camry, the oil change in the volvo, assembling my new kitchen island, changing the tstat on the volvo....

[632 Regal]

Thats not a good idea!

lol

While your up in there why dont you remove the belt and spin all the pullys and idlers for noise, crunchy feeling before you go and drive it again, better to do it now than maybe have a failure.

[DanDombrowski]

I knew someone was gonna say that!

Yeah, I suppose I could pop the belt off. If I remember correctly, rotated a few things when I replaced the belts about 6 months ago and didn't hear anything out of the ordinary. Mabye I'll check again. Its been making this noise for about a year now and hasn't gotten worse.