Hi,
I posted about a month ago regarding a 93 Toyota pickup losing antifreeze and the engine revving on its own. (original message below). After a second try at the Toyota dealer, they found a leak (where hoses connect to a valve at the firewall) and we thought it was fixed. The revving issue has gone away (for the most part), however I am still losing antifreeze (about a half gallon per week). When I turn off the engine (after my 25 min. commute), I hear the radiator dump antifreeze into the overflow container. They told me it is not supposed to do that. After it cools down and I open the radiator cap, pressure blows out the radiator and more antifreeze dumps into the overflow. The overflow container is full now. Does anyone have any idea what would be causing this? The radiator and thermostat are new and the cooling system was pressure tested (supposedly) twice for leaks, as well having a compression check done, which was ok. When they 'test' the cooling system, do they check for proper flow as well? Could it be possible that there is a blockage? Any ideas?
Thanks,
N.
(original message)
Back in April of 04, I noticed that after the truck warmed up, the engine would rev and then slow, when idling, by itself. I assumed it was in need of a tune up.
Then, during the summer, the truck overheated (since the antifreeze was gone, without an "apparent" leak). So, I ran water in the radiator, to try and find a leak, which I did not. I would have to add water every 2 weeks or so. Then when cold weather came, I replaced the water with the proper antifreeze/water mixture, having to add some, every 2 or three weeks.
Then I brought the truck to Toyota, for a "tune up", since the "revving issue" was still ongoing. They told me that the engine was not in need of a tune up, but that the radiator and thermostat needed to be replaced. I didn't understand how being low on antifreeze would cause a revving issue, they agreed that there was no leak, but insisted that replacing the radiator & thermostat would fix the problem, so I reluctantly agreed.
Now, (out $400), I still have the same problem, slow loss of antifreeze and "revving". I called Toyota and they said it could be the head gasket. However, it has no other symptoms of a head gasket (ie. no loss of power, no oil in the antifreeze or vice versa)
Toyota said that they will diagnose it at no cost, but I am afraid they will recommend another expensive (& possibly unneccessary) repair, to "see" if that fixes it.