On going cooling problems, electrical problems with cooling system

[g717xnm]

Hello,

I'm still have problems with my cooling system. I have removed a number of the problems - cleaned ground points, flushed system and removed blocked radiator and back flushed the blockage out.

My cooling system has had new thermostat, new water pump, new expansion tank cap and new coolant (50/50). So when I'm on the move things are now fine but the problem shows it self when I'm in slow moving traffic or stationary.

The car is a mk1 2Li on a g plate with air con (not working) rp4575. As it has air con there are 2 fans but i have only ever seen one working.

So the question is what should i check next?
Could it be the fans - How do I check?
Could it be a censer in the engine? How do I check?
could it be the display in the car showing me the wrong temp? How do I check?
Any help would be great

Thank you

Chris

This post has been edited by g717xnm on November 11, 2010 10:35 am

[Peter.N.]

Hi Chris

If its OK on the move but overheats in traffic I would say its definitly a problem with the fans. You need to leave it idling until the temperature exceeds normal by a reasonable ammount and listen for the fans coming on, if they don't check the sensor in the thermostat housing.

Cooling fan problems are quite common, the fans didn't work at all on two of mine but I only found out on one of the rare occaisions I got stuck in a jam, the first time was in France . There are a number of relays in the fan circuit, any of these could have bad connections or be faulty.

Peter

[noz]

Hi Chris,

I think this may be the answer you are looking for:-
http://club-xm.com/forum/index.php?showtop...id=39130&st=0&#

Cheers

noz

[g717xnm]

Thanks Noz,

That has rasied another issue. I have replace all of the relays with new ones sometime ago as i lost my fans because of a relay falling to bits!.

I check to day to see if my fans would run in slow mode if i turned my air con on and the answer is they do not. I only get one fan running when the engine is running at 90+.

So it seems i have lost a fan mode (slow) and one of my fans. I had a quick fiddle by swopping like relays for like relays just to see if i had some bad luck with one of the new ones but it didn't seem to resolve the problem.

Could this be a simple problem with the fan connection plugs or could it mean a fan has packed up and is stopping the 6v getting to the other fan????

Do you know which relay does what? There are 3 on the right hand side as you face the engine. I willl have to put a meter on them to see if the power is getting to them. Any ideas would be great.
I take it i could just put 12 v on each fan to see it they work?

Thanks chris

This post has been edited by g717xnm on November 12, 2010 06:35 pm

[robertmnorton]

Hi Chris,disconnecting the brown sensor plug should cause both fans to run at hi speed with ignition on.I found on one of my 2.1's that the fan frame connection on the l/h side wasn't mating with the fixed connector on the support frame.It only required the fan frame to be correctly re-seated to ensure that both connectors located correctly.
robertm

[Jan-hendrik]

How about hot wiring the inoperative fan? That will eliminate a possible cause.

[Jan-hendrik]

QUOTE

I take it i could just put 12 v on each fan to see it they work?

Oh, yes

[g717xnm]

Thank you for all of your help.

I have found the problem - It was a failed fuse under the bonnet but at first clance it looked fine. It was only when i put a meter across it was it identified as failed. Easy fix thanks heaven ..... welll until the next problem!!

Thanks again... but at least i keep learning more and more about these cars and there systems which is no bad thing, as it is the only way i can keep the car on the road.

[Jan-hendrik]

QUOTE

It was a failed fuse under the bonnet but at first clance it looked fine.