Hello, My nickname is Sonix and this is my first post. I am a fng at this so if I do anything wrong please do not hesitate to set me straight. I am buying a 1986 se5, 4 cycl, 5 speed stick, for 2000.00. I live in central Minnesota and the temps are in the teens. The truck is from Arizona. The body is rust free and everything else is in excellent mechanical shape. Except for the motor problem. Apparently it has some head work done recently. This is what is suppose to be the reason for the problem. The problem is that after the engine runs for a minute or two it starts to overheat. The temp gauge goes up and it starts blowing coolant back into the reservoir. A local mechanic thinks that the head gasket was installed incorrectly. I did not see a lot of exhaust like there was water in the exhaust. There is no sign of antifreeze in the oil nor oil in the radiator. Oil looks dark but somewhat clear and has no unusual smell. Water pump is new. The engine looks clean for a 86 with no noticeable leaks. Also for about 5-10 second after it starts it has a sound that used to be common when a hydraulic lifter was sticking. My guess is a sticky valve. Once the tapping stops the engine runs very smooth(is there a good additive to fix this, I used to use slick 50). I have been a grease monkey since about 1973 my first car was a 1946 dodge coupe, flathead 6 and a fluid drive clutch. So I am able to redo the work but would rather not pull the head unless I have no other choice. Things I have considered are 1-plugged radiator, 2-sticky thermostat, 3- plugged water passage in the motor (possibly gasket sealer), 4- mixed antifreeze which has gelled and plugging water passages in the motor or elsewhere. (would the heat from the engine melt the gell allowing it to flow?) Also the head gasket. So if anyone has any information or thoughts about my problem(s) I would be very thankful for your insight and help. Sonix

 

A 1986 B2000 originally had mechanical lifters. The later B2200 engines had hydraulic lifters, and some have swapped these between the two kinds of trucks.

Unfortunately, these have different head gaskets, and I'm not knowledgeable enough to remember which one is which and what you need to have checked. I know one of the engines has a restrictor and one does not. This issue has been addressed at MazdaTrucking.com, and either search there or ask your same question there.