Club 80-90 Forums

Hey guys n gals, I would really appreciate your help with an issue I'm having. So I replaced my thermostat (87° opening Febi Bilstein brand), water pump (metal impeller OE spec) and coolant. Ever since the temp has been running above half and up to three quarters. It will read 3/4 before the stat actually opens. Once the stat opens the rad fan kicks in and out when stationary after a little while and the dial never goes above 3/4. If I drive with the heater blowing on full in hot position it goes a needle width above half way but the stat doesn't open, the rad warms up a little but the return hose to the engine stays cold. I have bled the system a few times and no air is coming out and I have driven about 150 miles now but it is still doing the same. This is the second stat i have put in as initially i thought it was just opening late so I've put in an OE spec one this time and is still doing the same. I am completely puzzled and also a little worried as I am off on a 6000 mile Europe trip in 2 weeks. Any help would be really appreciated and thank you in advance for your time.

so the cooling fan is working at the desired temps and if it were a connectivity issue (ie corroded) I would expect the gauge to hardly move or be at least intermittent as corroded connections causes a resistance that's misinterpreted by the gauge.
So it points to the sender.

Assuming that you followed the baxter method of bleeding.

You can fit a lower temp stat (80 deg)

Thanks for your comments and advice. I fitted a new Topran brand temp sensor before doing all the other work and it read at half way all the time, stat opened and stayed at half.. fan kicked in etc etc...

I am wondering if it is a bleeding issue... I will have to find this 'Baxter's' bleeding method though I think..... Does the stat need to be open to bleed properly?

If I don't get it sorted before I go I may consider a lower temp stat or just taking the stat out since it's gonna be hot when I'm away anyway

Dont run without a stat. Ever. It creates back pressure that the pump needs to work against, otherwise the pump will simply thrash dead watrr and there will be no circulation or flow to the radiator.
Topran stuff is cheap generic btw... not great quality.

Thanks again for the post. OK. Point taken, sounds absolutely right too given where the pump is located. My next step I think is going to be to acquire another new temperature sensor from somewhere. I was thinking Brickwerks for a decent quality sensor? Would they be likely to have an OE spec one do you think?

Bleed correctly first.
Details in the wiki for bleeding. I re-posted Simon Baxter's treatise here recently. https://club8090.co.uk/forum/viewtopic.php?f=37&t=143891

You should be revving at a speed that will at least annoy your neighbours. I was glad when it ended.

I must admit that it is rather frightening when you hear it rev like that!

Yes the revving makes me proper nervous.
I too was glad when it could stop.


There is the bong method as well.

This is why you need a CU engine

Nobody needs a CU engine

I do a "let it get some pressure up, then crack the rad screw" method. I've never seen it in print, but it works for me. (Had to do it loads of times a few years back, flushing oil out of the system)

kevtherev wrote:There is the bong method as well.