'92 DE Cooling System Problem

[zsmith789]

Hey all first time making a thread, I apologize if this or something similar has already been covered.

First off a lil background on my car. Its a 92 SE automatic that was given to me roughly a year ago. Only noticeable problems then were your regular maintenance stuff (including a cracked coolant reservoir) I never noticed any overheating but within a month the radiator had sprung a leak, specifically it was on the top where the plastic meets the metal towards the driver side. So I replaced the radiator at that time with the thermostat following not too long after. My reservoir would shoot coolant out its gaping hole so I replaced it. I replaced the old water pump while I was in the neighborhood fixing something else. Upon inspection the bottom weep hole was very grimy, as if it had been leaking for quite some time. All this leads me to believe this has been an issue before I got the car.

A complete list of what I have replaced:
Radiator (replaced with OEM)
Thermostat (replaced with OEM)
Radiator hose (replaced with OBX hoses)
Reservoir (replaced with circuit sports ebay knockoff)
Coolant Temp sensor (OEM; also had a light coating of rust on it)
Radiator cap (@13 psi)

It may be worth mentioning my intake manifold cooling line had a light coating of rust on it, came off easy with CLR tho and the line looks fine now. Also I flushed my coolant lines after replacing the radiator and I attempted to bleed the lines after any replacement part.

Now the car doesnt overheat it usually sits right around the 2nd or 3rd line on the temp gauge like it always did before. If I drive hard the gauge hits halfway but has not even got close to the H. But after driving the radiator cap starts shooting coolant out its relief valve, if it doesnt come out there I notice steam coming from the rubber insulation between the radiator and front of the car, most likely another hole in the radiator. I tried bleeding it a sec ago and got nothing from the bleeder bolt but the radiator was spewing like crazy. I felt both my hoses the upper one was good and hot but the lower one was rather cool, making me think maybe I need another new thermostat. No leaks look present other than the cap pressure relief and spewing area hidden by the rubber.

Now for my questions, fellow 240 enthusiasts with more knowledge than myself. Where is this insane pressure coming from? It seems like maybe thermostat but it seemed to open fine the time before this that I bled it. And if I solve this pressure problem is that going to stop this radiator leak under the rubber? I thought I had seen somewhere under too much pressure the metal and plastic can kind of seperate but will fix itself when pressure is back to normal. And if that is not the case, what can I do to prevent having to replace everything all over again?

[Rambo24o]

this may help do an engine flush and check if the fan tunes on as u drive, the fan makes a big difference. If its the same try take the termostat out to check if its that.

[mfroelich]

Yeah I'd recheck the thermostat its not uncommon for them to mess up even when they're new