Arghhhhh!!!!!

I must post more problems with my crap car than anyone else on this whole forum :doh:

Anyway, I thought I had fixed my overheat problem. I stopped the leak, and realised the viscous fan was not performing at its best, and the A/C fans never ever came on no matter how hot the car got, so with the advice of a few members on here, to combat this I wired the A/c fans to a switch on the dash.

Bit of info:
1996 2.5dse auto
Originally the car never over heated since I bought it 2 month ago, first night I got it I took packed it full with people and ran them round often. Fine when towing.

Now it runs absolutely fine until I get more than 2 people in the car, or a trailer on the back. It over heats after about 15minutes with the extra weight.

Last night I took me, my girlfriend and a mate out, I got 15 mins up the road, noticed the temp gauge moving swiftly to the red so pulled over before it reached red. Let it cool, tried to drive on, 10 seconds started to move to red again, stopped as soon as I saw needle move. Got someone to pick them 2 up and I drove it home fine with the needle sat steadily in the middle. seems as soon as I removed the extra weight the car was fine.

Now I have tested the car since wiring the A/C fans to the switch, I went out on my own, as soon as I flicked the switch I could take the temp back down to the blue section within a minute, also when I put the heating on full and HI it would reduce the temp gauge by a small fraction. Last night I tried both these things and It made no impact on the temp at all, it either kept going up with them in, or on my own did nothing.

Does this imply that the thermostat is dodgy and was not letting water to actually get to the radiator for the fans to cool it? This is my thinking as sometimes I can run the car for ages and it stays in the blue, and sometimes it runs normally and I can use the A/C fans to change the temp, but last night I could not impact the heat at all with either the A/C fans or blowers in the car.

When it overheated I checked the radiator, both top hoses hot, hard, but could still squeeze them with some force. I opened the expansion tank to put some cool water in to cool it down quicker, took a while to let the pressure vent out, took about 5 mins, then once that was done I took the lid off fully. I must admit In my rush I did pull the cap off too quick and got covered in fluid as it gushed out. But the fluid wasnt boiling hot, it was roughly luke warm. Surely if it had overheated it would be red hot water, I should have scolded my hand surely??

Im very confused, at my wits end wits end with this car, I only bought it to use a comfy tow vehicle, and I cant even move the weight of 3 people any more.

This is what I have found so far:
Stopped the previous leak
No oil in water
No water in oil
No milk or cream in header
No water loss at all

Im planning to:
Flush radiator
Clean between a/c radiator and radiator
Change thermostat
Change expansion tank cap
Change water pump
Change viscous unit
Change radiator
(in that order, if one thing doesnt cure it I will move on to the next, cheapest first )

so to conclude,
-on my own it never over heats
-With me and another person it doesnt over heat
-3 people or more or trailer it overheats.
-Viscous fan not too good, but A/C fans wired to switch, which originally worked extremely well
-When overheated water seemed warm but not boiling hot
-Last night heaters on full, and A/C fans would not impact the heat at all
-Both hoses were hard but could be squeezed with force
-No problem with the head, no water leak at all, no water in oil.

Any one with any knowledge at all, even if your not sure, just give me an idea I can work at.

Thanks

In view of the comment about the temperature of the expansion tank, an air lock perhaps?

Pete

Pete The Biker said:

In view of the comment about the temperature of the expansion tank, an air lock perhaps?

Pete

Click to expand...

I would do above and then first three things on your list, seems odd that having 1 extra person can make a big difference,

May be, I have tried bleeding it before, and it worked fine all day until I got more than 2 people in. Will flush the whole system when I do thermostat and re-bleed it.

Cheers

I'd suspect the water pump. The pump has a plastic impeller that can crack after an overheating episode. If your DSE has overheated you should change the pump.

The other thing to check is if the baffle that forces the coolant through the rad is still there. Has been known to fail allowing the hot water to short circuit across the top of the rad instead of through it.

We have all been there with overheating diesels.
My experience is in order of priority:-
- thermostat sticking
- water pump impeller fell apart
- blocked radiator
- viscous fan u/s


in my experience diesel doesn't air lock if vent pipe from rad OK.

SpudH said:

I'd suspect the water pump. The pump has a plastic impeller that can crack after an overheating episode. If your DSE has overheated you should change the pump.

The other thing to check is if the baffle that forces the coolant through the rad is still there. Has been known to fail allowing the hot water to short circuit across the top of the rad instead of through it.

Click to expand...

Sorry stupid question, How do I check its still there, take the radiator off?Is it inside the radiator?