I'm still having my overheating problem with my 5.9. The mechanic did a compression test and found 130 in ever cylinder (129 - 132) so the compression is good. Its overheating and when it does it shoots all the water into the reservoir and fills it with air.We had the radiator cleaned and the top three lines plugged since they were leaking. Water runs through the radiator without any problems. The mechanic is telling me that it may be the radiator, even though it seems like it is okay it is really causing the issue. The truck doesn't always overheat, only after a while. Has anyone had any experience with this? Does anyone know if its true or not that it could be the radiator?
Thanks
Gerrit

 

I had a Toyota pickup that acted that way. Changed the radiator, life was good.

 

Try changing the radiator cap, if it goes bad it wont hold pressure in the radiator and spray into the overflow. That is the main purpose of it.

 

Why would anyone clean and repair a radiator anymore? I am shocked that you found someone that would service a aluminum radiator. You should just replace it and be done with it.

 

I agree with those guys. I don't think I'd replace the radiator just yet. You should be able to get your cooling system pressure tested. You've got something leaking. Could be as minor as the radiator cap to as bad as the heater core or head gaskets.

 

Yeah, just throw it away

 

I appreciate the input! yeah it was a small shop down the road that serviced it. The system is losing pressure somewhere, i just don't know where. Compression is good, cap is good, there is no moisture on the passenger side floorboard, the oil is completely clean, it just doesn't make sense....has me stumped.

 

Kind of curious as to what exactly that means.


Has the Tstat been replaced?

 

with that i mean that sometimes i can drive the truck for a while and it will be perfectly fine but other times it will overheat right away. It makes no sense to me. Yes the T-stat has been replaced and i've also tried running it without a thermostat in the truck an it still overheated.

 

I would go back to the place that 'fixed' your radiator and ask for a refund or credit toward a new radiator. I would guess that you probably paid to fix it close to what a new one would have cost. If you had 3 leak already, then you probably weren't too far from having more and that is probably what is causing your problems now. At least replacing it would help narrow down your issue and help prevent it from occuring again.