I have a 1990 teggy with a B18B LS swap, using the obd0 components and pr4 ecu. The problem im having is it keeps overheating. I can drive for arleast 10-20 minutes with no problem but then the temp starts rising and fluctuates depending on how fast im driving, if i take it up to a contstant speed it does start to go down to normal or if I just shut the car off for 5-10 minutes it’ll return to below the half way point, My radiator is basically new, Ive got two fans constantly blowing, no thermostat!!, no blockage in the hoses, no leaks although when it overheats the water in the resovoir gets very low or empty.
What could it be!!! I really hope I dont have to change the head gaset!
did you extend the wires to reach the coolant temp sensor at the t stat housing? because it will be there now as apposed to on the back of the block.
hmmm. i thought at first for sure it’s the fan not operating, but you say it’s on all the time.
could be the waterpump has packed it in. check to see if coolant is circulating correctly.
at normal operating temp, the upper rad hose should be hot and the lower cold if it is circulating through the radiator.
how about the rad cap? is it pressurizing properly? start small.
are you sure it is in fact overheating? your gauge sending unit may not be operating correctly as well.
if your coolant level isn’t dropping and you’re not blowing white smoke, i wouldn’t assume just yet that it is the head gasket. that’s not to say it couldn’t be though. may wanna run a compression test before you start pulling the head off.
i’d check circulation first, then try a rad cap off a friends car maybe. you wanna try and pin point the problem spending as little money and time as possible. if it’s not a head gasket problem now, constant overheating and cooling will turn it into one.
my car tends to overheat aswell but thats because i didnt bleed the system properly. I still need to do it but have been lazy.
im pretty sure yours would be that problem. Have you tried bleeding your cooling system?
theres a bleeder valve on the dist. side of your head and you need a 12mm wrench to loosen it and when you do loosen it, rev the engine via throttle cable and let it bleed until it shoots a constant stream of water. Once its constant tighten the bolt then the system should be free of air. This allows the coolant to circulate properly and should stop the overheating issues unless its something far more complicated, i.e. waterpump, etc.
make sure your overheating to start off with. use a temperature probe with a multimeter or one of those infrared thermometers and check the temperature of your two rad hoses. the temp gauge is known to go nuts on our cars and is terribly inaccurate.
and you should reinstall your thermostat.
my old teg used to “overheat” when driving on the highway, randomly driving around town. the more gas i gave it the cooler the engine was. until i checked the actual temp and found out the gauge/sensor whatever it was was defect.
Like Sirtef9 said you need to put your thermostat back in correctly it will not cool right with out it becouse when the thermostat is open it blocks off the radiator by pass that is used to warm up the motor.
Well the fans were blowing the wrong way, wooops!. I fixed the problem by flipping the wires. What a diffrence something so small makes. Thanks for all the help!
