first time on the forum and this is a long introduction but wanted all info out in the open. I've owned this truck for five years and bought it with only 40K miles knowing there must be a reason for the low mileage. I found the previous owner ran synthetic oil and I assume they treated it like a gas engine and didn't change the oil regularly because I had to replace the turbo that was gunked up beyond cleaning. Long story short, this has been a very strong work truck for me since the turbo replacement and now has 130K miles, just a baby for this engine.
I am running into coolant over flow issues and from what I have read on forums this is a common problem with these trucks. It seems to have an air lock or bubble in the system, pukes from the reservoir. I have gone through the process of burping, filling, burping to release any possible airlock best I can. Before I relaized the overflow issue I thought it was the pump, I know this replacement is a Bit#* and actually got the pump and special tools to do the job but getting no leaking from it so still not convinced. I read about the possibility of a bad head gasket and the over-pressure issue coming from the cylinder into the cooling system but not convinced about that either because I'm not getting excessive upper hose pressure. I checked the heater core and it looks great and i'm getting no smell in the cab. I have spent a lot of time under the hood observing this and also replaced the cap which brings me to my question........
Why is my cap constantly releasing pressure out of the reservoir even at very low pressure? I realized this when, with the cap installed and the truck idling, I put the overflow hose into a bottle of water and noticed a constant release of air bubbles, isn't this cap supposed to hold pressure in the system? The pressure seems very low and the upper radiator hose is not hard? I don't seem to be getting gasses from the cylinder, no smell? In idle, with the cap on and the overflow hose relasing air, the lower hose from the heater core to the reservoir constantly lets in a very small amount of air. The small hose from the top of the radiator to the reservoir is letting in foam bubbles and the reservoir level is constanly rising and falling. I took the overflow hose off the reservoir and put my finger over the outlet and all the fluctuation in the reservoir stopped, as well as the bubbles, and the reservoir sat normal. When releasing my ginger after about one minute there was not release of pressure from the tank and it went back to the fluctuation and and bubbles immediately. It seems like the cap wants to be a bit higher pressure before it releases, I realize it calls for a 15Lb cap but has anyone tried a 20Lb cap for the reservoir? If it were a head gasket leak and my finger over the overflow from the cap I would expect it to gain noticeable pressure but it does not.
Any suggestions?
I am running into coolant over flow issues and from what I have read on forums this is a common problem with these trucks. It seems to have an air lock or bubble in the system, pukes from the reservoir. I have gone through the process of burping, filling, burping to release any possible airlock best I can. Before I relaized the overflow issue I thought it was the pump, I know this replacement is a Bit#* and actually got the pump and special tools to do the job but getting no leaking from it so still not convinced. I read about the possibility of a bad head gasket and the over-pressure issue coming from the cylinder into the cooling system but not convinced about that either because I'm not getting excessive upper hose pressure. I checked the heater core and it looks great and i'm getting no smell in the cab. I have spent a lot of time under the hood observing this and also replaced the cap which brings me to my question........
Why is my cap constantly releasing pressure out of the reservoir even at very low pressure? I realized this when, with the cap installed and the truck idling, I put the overflow hose into a bottle of water and noticed a constant release of air bubbles, isn't this cap supposed to hold pressure in the system? The pressure seems very low and the upper radiator hose is not hard? I don't seem to be getting gasses from the cylinder, no smell? In idle, with the cap on and the overflow hose relasing air, the lower hose from the heater core to the reservoir constantly lets in a very small amount of air. The small hose from the top of the radiator to the reservoir is letting in foam bubbles and the reservoir level is constanly rising and falling. I took the overflow hose off the reservoir and put my finger over the outlet and all the fluctuation in the reservoir stopped, as well as the bubbles, and the reservoir sat normal. When releasing my ginger after about one minute there was not release of pressure from the tank and it went back to the fluctuation and and bubbles immediately. It seems like the cap wants to be a bit higher pressure before it releases, I realize it calls for a 15Lb cap but has anyone tried a 20Lb cap for the reservoir? If it were a head gasket leak and my finger over the overflow from the cap I would expect it to gain noticeable pressure but it does not.
Any suggestions?
