Quote:
Originally Posted by Fulcrum525
I went for a drive this morning and the bad cap theory is starting to turn a few cogs in my head.....
I drove to my indy to pick up a part (That hadn't arrived yet  ) {9 Miles backroads only}
Before I left there I popped the hood and noted that the hose was hard so I took the cap off and relieved the pressure.
Then I drove to Farmington {15 miles, some highway, max speed 65} I turned the engine off and let it sit for about 30 minutes....when I came back I popped the hood and checked the upper hose.... it was soft. I took the cap off again (I had a 20 psi cap in the trunk that I wanted to try but it didn't fit)
Drove home again {11 miles, highway, max speed 75) This time on the highway the coolant light kicked on again for a minute or two. While writing this I have been letting the car sit again for another 30 minutes. Just checked the hose....it's starting to go soft again but I did notice that there is coolant around the bottom edge of the cap on top of the coolant tank so something came out.....
Another thing....assuming that it isn't a bad head/gasket but that there is still too much pressure....what could be the source? Apparantly air getting into the system would be the culprit so the question becomes how is the air getting in? I should mention that I do have one leaking injector and the front cover on my engine has been leaking oil since this happened and it was not sealed correctly.
OM603: Freak failure of timing cover. 1987 300D
Perhaps one of these two areas is letting too much air into an otherwise good system? (I probably have no idea what i'm talking about but if it helps to know I might as well post it) |
Does not sound like combustion gas is leaking into the coolant. It does sound like you have a questionable cap. I'd go to Autozone and borrow the coolant system pressure tester and test your caps right in the store, also test a replacement cap that they sell, and buy one that fits your expansion tank and give it a try. The leaky injector and timing cover should have no effect on coolant system pressure.
As to the coolant level light, when it goes on, and you pull over immediately to check, what is the level in the expansion tank? The float switch is a magnet on a swing arm that acts on a sealed reed relay. There's nothing to clean. If the expansion tank level is not low, I'd replace the float switch. Don't buy a Meyle, or other "OEM" garbage float switch if you want a good one. Get a Mercedes unit. I bought one from Autoha@@@s and it failed within a year.