Why does this happen!!??

Car has been sitting for about a week literally not turned wheel because of a collapsed air spring...

Today went out to drive as normal and the temp guage went into the red once it warmed up (it was fine before), phoned breakdown......guy appears because I was EK (east kilbride) going to Clarkston about 4-5 mile's, but I was sitting just before the Thornton hall roundabout....

Anyway....he bleed's the system and all's well (or so I/we thought) I then drive into Clarkston after sitting with him dam 30 min's checking this n that.

Then not even 5 min's later after driving away the bl00dy temp goes into the red again!, but I manage to get home, Iv'e bled it again and been out just briefly, but it seem's to me (as he said too) like a faulty therm as it's opening to late (I prefer them to open to early).

But just why the hell does this happen as stated above....it hasnt moved at all for dam near a week and then this happens as was fine before..

What I forgot to say too....

The bottom radiator pipe (from the therm to the bottom left) is cold till the engine warm's up, this is when the temp gauge goes dam into the red then (hopefully) down to half way again.

But kinda move's from bewteen "12oclock" to "1oclock" infact dam near "1.30"....

Is this still a water pump....that's why the breakdown guy thought it was the therm....as it's not opening as it should..

Btw....mine's a 98' E39 523...will it still have this plastic w/pump or metal?

It wasn't as hot as this last week.  Your cars cooling system is just having to work that wee bit harder this week.

Your E39 will have the dreaded plastic water pump that the E34s had.

If you replace the thermostat, you are more than halfway there to replace the water pump.  The replacement water pumps have metal impellers and are far more robust.

I replaced all that stuff on mine in January and bled it and have had no problems. Read my post about halfway down the second page.

I found that you need to bleed the system with the engine running. VERY CAREFULLY though as you will be using a screwdriver very near the viscous fan blades when turning the bleed screws.

With the car's ar$e in the air you might have somehow made an airlock.  Just out of interest where exactly did you place the axle stand as I thought you can only place an axle stand under the sill jacking point - exactly where your trolley jack is positioned that you have just used to lift the sodding car into the air!

HTH

Andrew

The thermostat test isn't worth it anymore as on the E39 by the time you have the old stat out you are worthwhile putting a new one back in.  You have to take the thermo viscous fan off to get to the stat cover housing bolts.  Once the fan is off you are worthwhile doing all the jobs at once, hence why I also replaced my water pump when I didn't need to.

You would need a new O ring anyway and probably a new thermostat cover if the orange/red seal on the adjacent water gallery on the stat cover is showing signs of age.

Andrew

Andrew Rolland wrote: The thermostat test isn't worth it anymore as on the E39 by the time you have the old stat out you are worthwhile putting a new one back in.  You have to take the thermo viscous fan off to get to the stat cover housing bolts.  Once the fan is off you are worthwhile doing all the jobs at once, hence why I also replaced my water pump when I didn't need to. You would need a new O ring anyway and probably a new thermostat cover if the orange/red seal on the adjacent water gallery on the stat cover is showing signs of age. Andrew

thanks for the info andrew. i never changed my stat myself had it done by my local Indy, hence my lack of real knowledge on the subject