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rad hose
- Thread starter j555fjr
- Start date
Andrew Prince
Well-Known Member
- Joined
- Feb 23, 2010
- Messages
- 2,232
After inspecting/changing the cap (which you've already done), then the next easiest thing is to remove the hose and inspect it. Dead easy job other than catching the coolant 
Once you've checked inside and tested for perishing and can call it good, then the challenge is to look elsewhere. If you're removing the lower hose and draining coolant, you as well inspect the thermostat and pop it in a pan of hot water to see that it opens and shuts. What coolant is in there? Is it possible that it's water in there and you had a freezing issue? The more details you can give us, the better chance of a useful internet diagnosis 
Obviously we only know what you tell us, so there may be details you didn't think important that will give someone else a clue 
Also check the cooling pipes running to the rear cabin heaters - check these are working properly and there are no leaks. It sounds like the main heater matrix is working ok. I doubt any of the heaters are the cause the problem but worth checking just to rule them out - they have been known to corrode through and leak. And for this reason are often blocked off - if this is the case with yours, then the by-pass is worth checking out as something might have come loose or changed (people can do the strangest bodges
)
It's a bit of a bugger that this particular truck seems to have so many problems. Got to ask what history you have of this truck? It sounds like the previous owner did zero maintenance and then some! I.e. when was the rad last flushed? When was the 'stat replaced? Is there even a stat in there and is it the correct spec? Is the correct coolant in there? When was the water pump changed, if ever? (if your truck has done big mileage, then this may be worth changing as PM) You may just have to baseline the whole cooling system to solve the problem unfortunately.
As a passing comment, the 4.2 diesels have more than ample cooling from the OEM rad, so overheating one takes some doing (i.e. the whole cooling system seeing no flow). So don't rely on the system not boiling to arrive at the conclusion that all is well. And the guage is only helpful to indicate cold, warm-hot and boiling, and nothing in between as has been mentioned.
Cheers,
Once you've checked inside and tested for perishing and can call it good, then the challenge is to look elsewhere. If you're removing the lower hose and draining coolant, you as well inspect the thermostat and pop it in a pan of hot water to see that it opens and shuts. What coolant is in there? Is it possible that it's water in there and you had a freezing issue? The more details you can give us, the better chance of a useful internet diagnosis Obviously we only know what you tell us, so there may be details you didn't think important that will give someone else a clue Also check the cooling pipes running to the rear cabin heaters - check these are working properly and there are no leaks. It sounds like the main heater matrix is working ok. I doubt any of the heaters are the cause the problem but worth checking just to rule them out - they have been known to corrode through and leak. And for this reason are often blocked off - if this is the case with yours, then the by-pass is worth checking out as something might have come loose or changed (people can do the strangest bodges
)It's a bit of a bugger that this particular truck seems to have so many problems. Got to ask what history you have of this truck? It sounds like the previous owner did zero maintenance and then some! I.e. when was the rad last flushed? When was the 'stat replaced? Is there even a stat in there and is it the correct spec? Is the correct coolant in there? When was the water pump changed, if ever? (if your truck has done big mileage, then this may be worth changing as PM) You may just have to baseline the whole cooling system to solve the problem unfortunately.
As a passing comment, the 4.2 diesels have more than ample cooling from the OEM rad, so overheating one takes some doing (i.e. the whole cooling system seeing no flow). So don't rely on the system not boiling to arrive at the conclusion that all is well. And the guage is only helpful to indicate cold, warm-hot and boiling, and nothing in between as has been mentioned.
Cheers,
seems to have sorted itself out tbh, i know the antifreeze is ok because i drained and refind with toyota red myself. the heaters all work spot on the only other problem i had was electrical which is now sorted also.ive been in touch with the previous owner who had the car for 9 years and is a retired mechanic, he seemed to know his stuff and said that he done alot of the work himself, couldnt get him off the phone! i will know better this weekend when she goes on her first big run
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