land rover 90 (disco 200tdi )apparently overheating

[Tenz]

Hi,i've been rebuilding my land rover 90 for the best part of 2 years,on my first proper run out after about 3 miles down the road i noticed my temperature gauge going up when i put my foot down,it wasnt long before it was in the black on its way up to red,so i pulled over and the gauge started to go down at a steady rate,managed to get home keeping it at 30mph.
I did a quick search and fingers pointed at the ****part thermostat that i bought,i took it out and tested it in a pan of water and it didnt appear to be fully opening(or i convinced myself it wasnt),so i tried it without any thermostat and the temperature didnt go above a 1/4 so i thought that was my problem,however i put a genuine thermostat in and its done exactly the same(i did test it first)although tonight i noticed that when the temperature gauge went up my stereo turned on and off a few times and one of the warning lights is on really faintly,it was probably on the first time it did it, but it was daytime and never noticed it,it doesnt seem to be as hot as it says on the gauge, although the heaters are quite impressive,so im thinking ive got a earth problem ,but i dont understand why the fault isnt there when i run it with no thermostat???or is that a stupid question?

 

[Pricilla]

you may have an earth problem and it's always worth checking, however, as it's a disco 200tdi it's obviously a conversion, in which case it'd be worth checking you have the correct sender in there. When I did my conversion I'm pretty sure I remember the gauge showing too hot before I matched the sender to the gauge, ie if you originally had a normally aspirated engine in there...then that's the sender you'll need, unless the gauge has been changed to non standard. From memory I needed an adaptor

Sorry to be a bit vague, just my experiences that might help, hopefully an adult will be along in a minute to help you further

 

[bluedog333]

Disco 200tdi temp sender isn't compatible (properly) with the Defender gauge so it'll always appear to be running hot. It'll always read and be lower temp with no thermostat of course because the cooling fluid is always circulating through the block and rad.

 

[Tenz]

Thanks for the replys, I'm pretty sure it's got the correct sender in it as I ran it for about 3 months before I stripped it and it never had the problem but I suppose with it being stood for a while the sender could be faulty?
I meant that when it ran without a thermostat and the temperature stayed coolish the electrical problem wasn't there?

 

[Tenz]

Just to add the 200tdi was put in by liveridge in 2010 a couple of years before I bought it.

 

[bluedog333]

You might be right with your first assumption about a bad earth then. Not sure how the temp sender works exactly but I suppose without the thermostat the system is a lot cooler and there is less voltage from the sender to the gauge and therefore the electrical problem isn't as apparent. Or, I might just be making it all up!

 

[jamesmartin]

Hi,i've been rebuilding my land rover 90 for the best part of 2 years,on my first proper run out after about 3 miles down the road i noticed my temperature gauge going up when i put my foot down,it wasnt long before it was in the black on its way up to red,so i pulled over and the gauge started to go down at a steady rate,managed to get home keeping it at 30mph.
I did a quick search and fingers pointed at the ****part thermostat that i bought,i took it out and tested it in a pan of water and it didnt appear to be fully opening(or i convinced myself it wasnt),so i tried it without any thermostat and the temperature didnt go above a 1/4 so i thought that was my problem,however i put a genuine thermostat in and its done exactly the same(i did test it first)although tonight i noticed that when the temperature gauge went up my stereo turned on and off a few times and one of the warning lights is on really faintly,it was probably on the first time it did it, but it was daytime and never noticed it,it doesnt seem to be as hot as it says on the gauge, although the heaters are quite impressive,so im thinking ive got a earth problem ,but i dont understand why the fault isnt there when i run it with no thermostat???or is that a stupid question?

check the out put from rear of alternator as its revved ,the sender works on 12v from gauge been earthed through the sender ,the resistance of the sender reduces as temp rises meaning gauge rises., increased voltage will have the same effect ,and will effect radio

 

[Tenz]

Cheers for that I'll check it as soon as I finish work, and that explains why it doesn't do it with no thermostat.

 

[Tenz]

Just a quick update,I've sorted my problem,i added a earth strap from chassis to the engine, and cleaned up my earth points, and jobs a goodn, thanks for the help much appreciated.