So been trying figure out a problem with my ranger. The cooling system seems to be building excessive pressure once it warms up. E.g. The temperature gauge reads about half way. What it does once it gets to about operating temp the reservoir will begin to fill up till it’s almost full and then pressure release on the cap starts to kick in.
I did find a small pin hole in my coolant reservoir. I fixed that hoping that was the issue. I also changed the reservoir cap. Anyways, now when I pressure test it now it holds just fine even leaving it for an hour the gauge did not move. I did try also using a combustion leak test never changed color.
So I am thinking my problem is something like the thermostat, water pump ect… I want to change the thermostat, but both O’reiley and autozone want about 140 bucks for one. The ford OEM part (1S7Z-8575-AG) the nearest dealer wants over 200 dollars for it. I do see cheaper replacements online like 30 or 40 bucks. This thermostat has built in housing as well an electrical component. Has anyone used one these cheaper ones or was it junk?
Oh Also one other thing the fan never seems to kickin before this issue at which point I shut the truck off since I don’t want coolant getting everywhere. However if I turn my heat on the radiator fan will turn plus the AC compressor turn on and off time to time, but when my heat is on the radiator fan running seems to stop this issue. I can leave idle for over an hour without issue if my heat is on.
Coolant is not overfilled. Originally was at max and was still doing this. I lowered it to about halfway between the min and max line. Although now it’s at the min line from some coolant spilling out due to this issue
I did also try burping and squeezing my rad hose to massage any air out. I have let run without the cap on to ensure there was no air. No bubbles or anything till it starts to get operating temperature at which point without the cap the system will rapid start to rise in level and bubble. With forscan that’s around 200F reading both head and coolant temperature or middle of the temperature gauge in the dash (not near the redline).
Like this was why also tried a combustion leak test cause I was worried about a head gasket, but never did change color. Also did check the indicator fluid directly on the exhaust to make sure it was good and it changed color there, but not from the cooling system.
This morning before I went to work I just did a compression test on all for cylinders cause still worried about a head gasket. I got about 180 PSI plus or minus a couple PSI on all of them. So that seems good. So I am definitely thinking it’s something like the thermostat or water pump.
I mainly was curious if anyone had used any of cheap thermostats and had good results. Cause the thermostat is not cheap for this vehicle since it has the integrated housing and a heating element for the computer to open it up sooner if it decides too. Compared to a normal thermostat on other vehicles I have owned.
Like an OEM water pump is cheaper than the dang thermostat if you look at this picture. https://imgur.com/a/nIDXAfF