Noctule wrote:Exactly what were your overheating symptoms? You've mentioned the coolant exploding out of the reservoir when hot... that doesn't sound like overheating as I can't see how the Di can get that hot, the fan is always running.
The coolant pipes will go hard as the temperature and therefore the system pressure rises, but it's a good idea to check when the pipes go hard. If they go hard when the engine is still cold then you have a different problem, probably head gasket. Hot exhaust gasses could be finding their way into the coolant causing a massive pressure rise, even when cold. You only need to run the engine for a few minutes for the pressure to rise to explosive levels as there is nowhere for the gasses to go unless you take the expansion reservoir cap off. If you can then run the engine with the cap loose without overheating then that could be the cause.
My guess is based on experience, on an autobahn near Cologne a few years ago. 2 days into a 2 week holiday. Needless to say the holiday ended. Thinking back I would've slackened the reservoir cap and carried on.
Mat
I'm sorry you had a problem.
I'm basing my diagnosis of overheating on two things: the temperature gauge shows hotter temperatures during driving, but only when I'm standing in a traffic jam in the city; on the highway it seems to run "normal", or just a bit to the right of center on the temp gauge, but as soon as the van slows down, and I'm in a city, especially at a stop light in heavy traffic, I see the gauge go more and more to the right, to the redline (but so far it has never reached the red area; the coolant explodes out of the reservoir cap before the gauge shows the temp is in the red area). This happened on two trips prior to this repair I carried out. So I assumed it was the radiator, or a collapsed lower radiator hose (the lower hose did not show signs of any leaks, but after I took it off, it appeared weak, old, not in good condition). So, I have installed a new radiator, and new upper and lower radiator hoses, and a new water pump. Those should all be working properly now, yet I have the same symptoms: the engine runs perfectly now , and after about 5-10 minutes or so, it seems to have reached proper operating temperature (now the gauge reads almost perfectly in the center, slightly to the left in fact). Yesterday I let it run for a total of about 15 minutes before shutting it down, but just as I was about to turn it off, I noticed that coolant had erupted out of the reservoir tank (which did not have a cap on it). I shut down the engine, cleaned off the coolant, and then put the cap back on, and restarted the engine to see what would happen. After the engine got warm, the coolant once again burst out of the reservoir cap, just as what happened on my trips a couple months ago, prior to this work I performed.
I do not notice any coolant in the oil (not in the old oil, because I changed the oil during this service, nor in the new oil yesterday). No coolant in the oil, and no oil in the coolant. I thought that would rule out any head gasket problems, but I could be wrong.
