engine temp too low.....then too high

[lowthorpe74]

Help.........Please!

I have a 97 D8 3.0 V6 SE which is driving me mad. Engine water temp has suddenly decided to do whatever it wants. One thing is clear, the fans are not kicking in. As long as I go over 30mph the car doesn't overheat. I've replaced the temp sensor next to the thermostat on the engine, what should be my next move?

cheers for help on this.

[steve_earwig]

Hi. Umm, check that the fans actually work. I think your car will have 2 fans and 3 relays, the connections on the relays can get nasty and the brushes in the motors can (and probably have, by this time) wear away to nothing.

[lowthorpe74]

Hi matey

Fans are not seized, they turn freely. I've seen lots of suggestions on different sensors to replace but slightly confused on what should be the correct 'next step' as a systematic approach to finding the fault.

Internal heating is running OK and the AC appears to be working OK (I haven't checked to see if the fans kick in when AC switched on)

I just don't want to get into the realms of removing body parts just yet if it can be avoided.

On the plus side.........she runs great apart this niggling issue

[steve_earwig]

I didn't say seized, just the brushes may have worn to the point where they don't pass any current any more. Or the relays are rusty pieces of junk. Relays here - viewtopic.php?f=1&t=14890&p=141513&hili ... pg#p141513

[lowthorpe74]

Ah OK.

Picture link will be a massive help.....Thanks. I'll have a look in the next few days to see what's what.

No doubt I'll be in touch!

Cheers buddy

[lowthorpe74]

Just another quick one. If the brushes have gone.....are they easy to replace? I sense that a time off the road might be needed!?

[rwb]

Definitely check the relays.

If it's not that then it would be good to get a PP2000 session since you can tell the fans to run, and so therefore that they work.

Scrap fans seem pretty easy to get hold of, and certainly on the HDi 90 you can replace them without removing the front bumper.

[steve_earwig]

a 97 D8 3.0 V6 SE

Not quite the same thing dear chap

Just another quick one. If the brushes have gone.....are they easy to replace? I sense that a time off the road might be needed!?

I did it on mine but it's not funny - viewtopic.php?f=3&t=2974&p=38735&hilit= ... hes#p38735 although this is probably a better way of getting to them without removing the skin from all your knuckles - viewtopic.php?f=3&t=4911&p=48420&hilit= ... per#p48420

But let's see what's up with the relays first, usually 1 fan will go before the other and then you'll notice the remaining fan pulsing on and off as the pressostat tries to keep the temperature steady.

[mjb]

There are THREE coolant temperature sensors on the ES9J4 with green, brown and blue plastic on the connectors IIRC, and only one of them directly affects the dashboard gauge. If you're near ST5 postcode, you can have my old ones for free. I think they're working...

If you unplug one of them (sorry, can't remember which) you should have the fans coming on at full speed when you turn the ignition on. If your temperature gauge is going all over the joint, I'd say it could well be that the coolant just isn't hot enough for the fans to kick in.

[lowthorpe74]

Cheers for all the info chaps. I'm no where near ST5 but thanks for the offer. My spidey sense is telling me that I have long day Saturday of swearing and eventually losing skin from my knuckles at some point. I might as well crack on with changing the thermostat while I'm at it.
Let you know how things progress.
Cheers