I have a 94 with about 280,000 miles, which i bought used a few years ago, and have been having cooling system problems ever since.
first issue was just making a noise like a coffee percolator from the expansion bottle after parking, complete with steam and some coolant coming out the overflow. Then the bottom tank of the radiator blew off. Had a shop reseal the tank, got a new cap, filled the system, forgot to put the clamp on the tiny radiator hose, got hot, but used some wire to clamp it and refilled the system.
drove fine for a while after that, but then started to have the current problem, where the heater would stop flowing, and the temperature would start to climb. Pulling over and holding the idle high would bring the temperature down, and once it got back to normal the heater would start flowing again.
I thought that it might be a head gasket leak, so I ran a combustion leak test, with the detector fluid. The fluid didn’t change color at all as the engine warmed up, and didn’t change while it was hot, and then the coolant got into the tester. During the test the heater hose never got warm, despite being set to full hot, and the two upper rad hoses made the thumping sounds of air traveling with the fluid, and plenty of air was pushed through the tester.
I’ve started to suspect a small leak is letting air into my system, so I’m planning on bypassing the heater system by running a hose from where the PHH is to the return fitting by the pump, to see if that makes any difference, but if that doesn’t work I’ll be out of ideas. Any pointers?
first issue was just making a noise like a coffee percolator from the expansion bottle after parking, complete with steam and some coolant coming out the overflow. Then the bottom tank of the radiator blew off. Had a shop reseal the tank, got a new cap, filled the system, forgot to put the clamp on the tiny radiator hose, got hot, but used some wire to clamp it and refilled the system.
drove fine for a while after that, but then started to have the current problem, where the heater would stop flowing, and the temperature would start to climb. Pulling over and holding the idle high would bring the temperature down, and once it got back to normal the heater would start flowing again.
I thought that it might be a head gasket leak, so I ran a combustion leak test, with the detector fluid. The fluid didn’t change color at all as the engine warmed up, and didn’t change while it was hot, and then the coolant got into the tester. During the test the heater hose never got warm, despite being set to full hot, and the two upper rad hoses made the thumping sounds of air traveling with the fluid, and plenty of air was pushed through the tester.
I’ve started to suspect a small leak is letting air into my system, so I’m planning on bypassing the heater system by running a hose from where the PHH is to the return fitting by the pump, to see if that makes any difference, but if that doesn’t work I’ll be out of ideas. Any pointers?