1999 Ranger - High Pressure - Coolant to Overflow

I have a 1999 Ranger that has started creating high pressure in the coolant system and is pushing the coolant into the overflow tank (sometimes spraying the motor if I don't empty it).

The temp guage does spike hot about 3 miles into any drive and then returns to normal. When the motor is turned off, there is heavy bubbling back through the overflow tank.

It's got 107k miles. It's the V6 that runs either gas or e86.

New radiator, new battery, new tires, and lots of other new stuff.

Two questions....do you think this is a cracked head(s) or gaskets, and if so, is it worth the cost of replacement given the miles. Body is in great shape. Thanks for your input.

Is it possible your thermostat is not opening and causing the engine to over heat. Ive got 150k on my 94 ranger an hope to drive it a few more years, Its been extremely reliable and comfortable transportation. I would start by checking the thermostat, A mechanic should should be able to pressure test the cooling system and give you a good idea where the problem might be

i was having the same problem on my 91 3.0
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-turns out the smuck who helped me do some work put the thermostat in upside down


so it could possibly be an issue with your thermo

try replacing it with a lower temp thermo

also get a system flush, ive seen somepeople fill their systems with bars leak and it causes more problem then trying to solve...


not saying you used it but you mught have some kind of blockage in the system

The bubbling is of serious concern. Fill up your cooling system so that you can see the water level in the radiator. Run your engine without the cap and check for any bubbles coming out of the radiator fill. Gun your engine a couple of times and see if the bubble increase in frequency and intensity. If this is what you observe, it's definitely head gasket problem between the chambers and the water jacket. As a further check, either pressure test your cooling system or take a compression test of your cylinders. If the problem is only in one bank, it may be worthwhile to pull the head and install new gasket.

Thanks to everyone for your reply. Turns out this was a serious problem. A crack in the head gasket. A very small one....but enough to give me fits for a few weeks until I bit the bullent and spent the money to fix it.