Thread: Running hot

<span style="color:blue">pull out the thermostat and test it......
it sounds like youre not getting flow......


is the pump you bought a land rover one or generic...?</span>

I agree . Change the thermostat. They are only about $20. When you refill the engine, point the car steeply up hill, so that the radiator is the highest point. My 3.9 has a filling point in the heater pipe which runs along the top of the RH rocker but early ones have the old system with no bleeder I think.

Just what did you do to the viscous?
In any case once you are doing about 50KMH , the air flow through the radiator takes over. ( unless you do have the fan on backwards, but if I recall it still pulls but not as well)

I hope you have not damaged the motor with the overheating. It is not usual to pressurise the cooling system with a blown had gasket as they usually leak into the valley. There are only waterways at each end of the head, and only the back ones flow through from the block to head. However it is possible. A slipped sleeve and cracked block does this.

Best of luck and lets hope it is a jamming Thermostat. How long since you had the radiator cleaned? How long since new hoses? maybe one collapsed. Make sure there are no kinks in the bottom particularly.
regards Philip A

I haven't had a thermostat for approximately 18 months. I've never had a problem till the water pump started leaking from the bearing late last year. I pulled the old one off and put a new one on. I can't see any way possible that I could have put the fan on backwards. It's a simple matter of screwing it straight onto the front of the pump. One way off, one way on.
The water pump is a LR one from British 4WD.
I thought maybe that I put the belt on wrong but I can't see how it could thread any other way.
The engine never overheated enough to cause any damage, I was pretty careful there.
The radiator was flushed last weekend, I did it at home with some of the radiator flush crap you buy. Seemed as though it was pretty good. I could put the garden hose in the top radiator hose and see it coming out the bottom hose extremely well. Reversed the flow with the garden hose and it came through pretty well the other way also.
The gauge is only sitting slightly above where it's always sat, but as soon as you stop the engine it spews coolant everywhere, and it smells a little hot.

It wasn't what I did to the fan that was an issue, but what I did to the old water pump it was attached to. I hac to cut the damn thing off with a grinder. That said it definately works fine, my question is would it possibly be cutting in too hot?

Aha a clue!!!
You said belt so I think you have a single grooved belt. there is a possibility that you put the belt on the wrong way, and are running the pump backwards.
If you have a CD manual, have a look at the belt layouts .
Seeing that it started when you replaced the pump , that is the first place to look. You said you were running without a thermostat then put one in. Even though you flushed the radiator that will tell you nothing. I suggest that you have it rodded.
Regards Philip A

see http://www.roversnorth.com/RRD04/RRD04_21_...RD04_page22.htm
Regards Philip A

I thought there may be the possibility that the coolant isn't getting into the block and heads without the thermostat, even thogh I've been running it trouble free without a thermostat for 18 months this is the first time I've drained the system.
Could this be the case, the coolant is just taking the easy route through the system as the bypass is not closed creating an airlock in the engine?
I couldn't find the belt config on my disc, and the link you posted shows a lot of red crosses and doesn't show the 3.9 serpentine diagram.
I really can't see how I could have put the belt on wrong, though I've looked as the thought crossed my mind also.

<span style="color:blue">did you compare the old pump with the new one when you had them both out.....
were they identical...?




have you got the restrictor plate from the thermostat in the engine....?

if the water is flowing through the system too quickly(no thermostat) it may cause overheating
due to it not being in the radiator long enough to cool down......


are you sure you are getting coolant flow from the new pump.....?
disconnect the radiator hose (engine cold) and start the engine to see if its pumping
water out......

its also possible that the rad flush you ran through the system may have
loosened some scale or crud from in the cooling system which is now restricting flow
by clogging up the radiator tubes....how much dirt came out...was the system
clean or really dirty when you flushed it out......

and i hope you didnt pour cold water in a hot engine.......</span>

<span style="color:green">F - OVERHEATING

1 . Poor circulation
2 . Dirty oil and sludge in engine.
3 . Radiator fins choked with chaff,
4 . Incorrect ignition timing
5 . Insufficient coolant
6. Low oil level
7. Choked or damaged
8 . Dragging brakes
9 . Overloading vehicle
1 0 . Driving in heavy sand or mud
11. Engine labouring on gradients
12. Low gear work
13. Excessive engine idling
14. Inaccurate temperature gauge
15. Defective thermostat</span>