Overheating Problems!

Overheating Problems!

Author
Discussion

ssc1

Original Poster:

456 posts

260 months

Monday 4th August 2003
quotequote all
yet another problem to sort out , its overheating now , it sits at 90c for about a mile from warming up then climbs all the way to 110c and stays there no matter what i do , have changed the stat for the 74 one but that made no diff ,changed the temp sensor and the otter switch and the temp gauge and had the fans running all the time as well, now one would expect the thing to run a bit cooler when on the move as it gets air over the rad but no it stays at about 105/110 all the time and thats with the stat removed as well, so i think that i have either got a blocked rad or a dodgy head gasket , but it dont pump water out at all so i have my doubts about the heads, any ideas before i give up and try a specialist..

HeyAndy

423 posts

248 months

Monday 4th August 2003
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check for an air lock. had the same problem on my wedge though i'm not sure if chimp owners will suffer the same problem. its worth a try though.

Incorrigible

13,668 posts

260 months

Tuesday 5th August 2003
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Are you sure the gauge isn't reading high, even in this weather with the fans permanently on shouldn't get above 90

>>The system is full of water isn't it

>> Edited by Incorrigible on Tuesday 5th August 10:14

ssc1

Original Poster:

456 posts

260 months

Tuesday 5th August 2003
quotequote all
have two gauges and they are both reading the same (bought a new one) , so with no stat fitted it runs at about 105/110 all the time , even when cruising at 70 on a clear road in the evening when it is cooler..

pies

13,116 posts

255 months

Tuesday 5th August 2003
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You have got the caps on the swirl tank and expansion tank on the right way round, springy one on swirl tank

trefor

14,635 posts

282 months

Tuesday 5th August 2003
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It might just be the pressure cap on the expansion tank is not holding pressure. If it's the blue screw type one it can be replaced at a VW dealer.

An airlock would be my second guess too.

T/.

Incorrigible

13,668 posts

260 months

Tuesday 5th August 2003
quotequote all
If it's not holding pressure at that temperature you'll loose a lot of fluid

SSC you say you've changed the gauge, what about the sender ?

If it's still running after all this, and you aren't using fluid, and the temperature is constant, I would guess that the real temperature is around 85-90

Take it to a garage and get the temperature measured properly, you need to be sure

ssc1

Original Poster:

456 posts

260 months

Wednesday 6th August 2003
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its only got one swirl chamber and the cap seems ok and it dont have an expansion tank , i did change the sender unit as well but no joy and its not loseing fluid , i did attach a heat sensor from my multimeter and that registers the fluid as 82c i have checked the accuracy of the multimeter with a boiling kettle and that is showing 98c when the water boils, so i am thinking as you have said an airlock posibly around the temp sensor , is there a special way of bleeding the rover unit, as i dont have a steve heath bible i dont have any info to hand and i just fill the system and bleed it out of the rad bleed screw with the heater set to hot , i do this with the engine off is this right , and is the pressure cap just a normal one from a VW dealer, what psi is it rated at....

19560

12,722 posts

257 months

Wednesday 6th August 2003
quotequote all
With wedges final bleeding needs to be done with the engine on but starting from cold so that the water doesn't overflow.

shpub

8,507 posts

271 months

Wednesday 6th August 2003
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Air lock around the temp sensor.... I don't think so.

I think you have the wrong sender for the guage. Your car is an early one and they changed the instruments more times than whatever. Some even needed a trimming resistor. If the multimeter is reading 82 degrees that is normal so I don't think there is a problem except for a duff reading temp instrument.

ssc1

Original Poster:

456 posts

260 months

Thursday 7th August 2003
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having talked to some electricians at work they agree about the gauges being at fault as i have confirmed that the multimeter is reasonably accurate and that the water coming from the stat area is reading 82c whilst the gauge goes happily up to 105/110, it looks as though the wiring is either shorting somwhere or the inline resistor is at fault, we have a test set at work for checking this out and will tell me what resistor i need to get the gauge to read just right so that it matches the meter reading, decca/dacca or degga box somthing like that so i will try that as well as setting the temp sensor in boiling water with the lead on it and a lead to earth and see what the gauge in the car shows, i might add that all the gauges are from a later car with the alloy surrounds and not the black ones as should be fitted this is an early 94 car and a previous owner had thenm all changed dont know why though, and i'm having the rad recored with a new modern core as the rad specailist said the the range rover rad had a very ineficient core fitted as standard....

shpub

8,507 posts

271 months

Thursday 7th August 2003
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If they have changed the instruments then unless they changed the senders as well, none of them will be accurate including the speedo which could explain why the car is not pulling beyond 120 mph (indicated).

Rev counter should be OK though...

The instruments are not drop in replacements.

ssc1

Original Poster:

456 posts

260 months

Friday 8th August 2003
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so it turns out that the rad was more than 50% blocked and has now been recored so that should be ok . but the gauges were replaced by a TVR specialist so you would have thought they should know what they were doing , once i have sorted out the temp gauge i will have to look at the speedo, i gather that it should be about 30mph per 1000rpm as i have the later gearbox fitted, will the oil pressure gauge also be reading wrong as well

Podie

46,630 posts

274 months

Friday 8th August 2003
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What about a mod-wise fan thingumy...?

ssc1

Original Poster:

456 posts

260 months

Tuesday 12th August 2003
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got the nice recored rad in it today and it dont go over 90c at all and that was with it sitting in traffic for over an hour but i did have the fans on all the time and once on the move the temp comes right down to 80c so i will be looking at fitting a power temp otter switch to keep things in check and have the fans controling the heat without them being on all the time as it never went above 75c in the evening and a nice new swirl pot cap from the VW dealer, so its running just a little too cool at nite. thats that problem solved now for the clicking exhaust ....