91 Ranger Cooling System Problems

I have a 91 ranger with a 3.0L engine and a manual 5-speed. Recently it began to boil over into the coolant resevior every time I drive it. I was reading through the forum and read a post about the same thing and the solution they gave was to take out the thermostat. I was wondering if there were any possible problems with this solution? Any opinions would be appreciated. Thanks Warren.

Do not remove the thermostat. start your vehichle cold with the radiator cap off aloow to warm up completly, If you see bubbles in the coolant then you might or probably have compression escaping the cylender into the coolant. Air does not transfer heat and the bubbles dont have to be big they might appear as carbonated soda bubbles. if this is the case you have either warped a head or blown a head gasket, but thats only what I think. try it out you may not like the news but you will know whats going on. also Ive heard that running a vehicle without a thermostat will make computerised controlls over compensate, and its only a band aid to the immediate problem.

Hope this helps.

also Ive heard that running a vehicle without a thermostat will make computerised controlls over compensate, and its only a band aid to the immediate problem.


Yes, removing the thermostat will help, but the radiator won't be able to hold any water back to be cooled. On long stop and go trips may cause you to overheat eventually. Good thoughts about the air in the cooling system. That statement is correct about the computer. What actually happens is that the computer uses a couple of tables of data when you first start the truck. Once everything gets warmed up, it starts using the o2 and such to help calculate the air fuel ratio. If the engine never gets to temperature (160 degrees?), the computer will never stop reading from this table, which is configured a little rich. Better rich than lean. I believe you would be safe to run a 180 degree thermostat, and it should help a little with pining if it's an issue (For MAF equipped trucks).

Pete

A trick to help your coolant system work more efficiently came to mind. Now this probably not going to solve your problem, but when your cooling system gets fixed and its time to install your next thermostat it will aid in preventing a future overheating problem.

All you do is drill an 1/8" hole in the flange of the thermostat and install the thermostat as normal. This helps equalise the pressure of your coolant.