Isuzu Trooper Owners Club UK™

[GJones]

Hi,

Was hoping someone has maybe had this problem before and would be able to pass on their knowledge.

Symptoms:-

- Once up to operating temperature the truck is pumping water in to the header tank (which eventually overflows)
- Top radiator pipe is being pressurised
- Been told by mechanic friend it is not overheating that is causing the water to pump in to the header tank (he checked temperatures over the entire system using a temperature laser gauge)
- At operating temerature the bottom and top pipes are hot, the bottom is very slightly colder
- The following is clean and not contamintated at all: Oil, Water, Diesel
- Getting hot air through the heaters (as long as it's not lost too much water)

What I have done so far:-

- New radiator cap
- It had a new water pump about a year ago
- Had a "sniff" test done on the both header tank and radiator and this has come back 100% clean
- Check for leaks in the water system and can't find any
- Removed the thermostat completely (left the circular seal in through)
- When removing the thermostat there did not seem to be any water in the block
- The problem seems to be worse now that the thermostat is removed.  Still seems to blow water in to the header tank at the same rate but now the temperature gauge goes above normal after a while and the heaters blow hot and cold (seems to be in a cycle), this could be down to not enought water in system (although when thermostat was in it never did this with similar water levels present)
- Not sure if this was a symptom before removing the thermostat or not but the middle of the radiator is cold even at operating temperature (I got the radiator second hand about a year ago so not sure of it's history, I have to admit to having put radweld in the raditor but this was after the the problem presented itself, put a flush through it since)

The plan now:-

- Get a brand new radiator and fit
- Get a brand new thermostat and fit
- Go a good run and see if it's still pumping water in to the header tank
- Been told if it's still pumping water in to header tank after this then it's head off time

Suppose the question is, have I missed anything i.e. are there any other checks I should carry out?  Has anyone else had anything similar to the above and what did they do to correct it?

Regards

Gordon

[Google]

[Browndoff]

I had the same problem when I first got my Trooper - I replaced both Thermostat and Rad-Cap - but, logically, it can only have been the rad-cap [which had a ragged rubber-seal!].

It's supposed to hold the water in the radiator until excess pressure forces an overflow - which should be a SMALL quantity - just three-quarter-filling the bottle when hot and draining BACK into the rad [by siphon-action] when cold. Could it be just that your return-line has an AIR-LEAK - so that it CAN'T siphon the water back into the cold rad??
_________________
2002 LWB Trooper 3.0L
I've done some major repairs, including replacing half-shaft, replacing fuel-injectors etc.

[GJones]

Great news, replaced thermostat and got a brand new radiator and all sorted now. Installed a second hand radiator about a year ago and think that was the problem. Regards Gordon