I am going to lay this out with what I know, what I suspect, and what I have done... not in that order, but I think you will follow along.
Background info: Last fall I had the timing belt replaced so new water pump. All winter it was really hard starting and I was blaming the timing being off just that little bit. The diesel mechanic that did the job ran into a few problems - not the right tools and then the wrong parts sent - so I was blaming him on being in a hurry to wrap things up.
Before that, and getting worse after, I have had to add coolant. At first every couple three months and then every couple three weeks. About the time of the timing belt I put an inline thermostat in to finally get some heat in the cab.
Middle of this summer I started having overheating problems. I would drive for about five miles, three if I hit the hill leaving work, and the gauge would shoot up, bells would ring, and I would pull over. After a couple of minutes the gauge settles back down, rapidly, to normal (12 o'clock on the gauge) and all is good no matter how hard I push it. Like the thermostat finally opens.
About a month or so ago I finally tire of this and decide to really look into this. I pull out the inline 'stat put it in water on the stove and see that it doesn't open up until just about boiling (210*). Ah-ha! New 'stat ordered. When it comes in I flush the coolant, new 'stat, bleed the system, and I am good. No problems. Total behavior not even using coolant.
Last week it started the overheating thing again. I read on this forum that it could be air in the system, and I thought that maybe I didn't get all of the air out as I did have to turn the heater on in the morning. Yep, more air in the system. So I bleed it again and it still overheats the next morning. And more air in the system when I bleed it again.
So here is what I know: Air/pressure in the cooling system; steam when I remove the oil cap; continued loss of coolant - however this could be from the over heating. However, the oil doesn't have the signs of water in it, other than the steam. In other words it doesn't look like mayonnaise on the dipstick.
Another thing I have done is replace all of the factory spring hose clamps - on top of the engine, in plain site - with band hose clamps.
Tonight I am going to remove the inline thermostat and just let the engine run cool.
So did adding the inline thermostat build up enough pressure to rupture the head gasket from what may have been a small leak? Am I just jumping to the worst conclusion?
I have not done a compression test which I know will give me a definitive answer. I have the means to do it, but not the best means.
I guess I am just looking for opinions right now. I want to keep Prudence running and I have an appointment scheduled in November to re skin the doors and take care of a couple of other rust issues. This is our adventure vehicle and I do really like it as it is more capable than many give it credit for.
Thanks for your help and opinions!
Tad
