1991 Honda Accord Overheating

Have it block and pressure tested-do the block first to pinpoint a combustion leaking into the cooling system or a gas analyzer to sniff for hydrocarbons at the radiator fill neck.

Pressure test: do not do a pressure test if there's leakage at the headgasket this might cause coolant into the cylinders and lock it up or bend a connecting rod if cranked thereafter. The headgasket should be repaired before doing the pressure test.

If the block and pressure test passes check the following: Thermostat, Pressure test the Rad. Cap, Clogged radiator, Fan clutch, Radiator electrical fan, collaspe hoses, water pump

Hi kayvan,

If you did not bleed the system, do it.

Hi kayvan,

At top part of the thermostat housing you will find a 12 mm hex nut with a hole, that is the bleeder nut.

Unloosen it a little and top up from the radiator neck till coolant comes out of the bleeder nut. Retighten the nut and keep topping till the radiator is full.

Start engine with radiator cap off. (If coolant shoots out, no need to test further, the head gasket is blown) If coolant level in radiator drops, keep topping up, after 5 mins, turn AC on and run for another 10 mins. Top up whenever necessary.

Bleeding is now done, close radiator cap.

Good luck.

Hi kayvan,

If the thremostat is not immersed in water, it would not work. If you bleed from the bleeder hole, water would get to the thermostat.

If you AC is not working, skip that part.

If the engine overheats and the radiator and AC fans don't start working, you need to check if they are faulty.

When the engine starts to hunt after starting for a short while, you need to check for blockages in the small hoses connected to the EACV, fast idle and throttle body.

A used radiator is not the problem, if it is clogged, at least it will take some time before it overheats.

Hi kayvan,

If the engine temp is high when you turn it off, the fan would work for a short while. If it happens most of the time, there is a lack of coolant in the system. If the fan don't cut off after more than a few mins, the fan relay is faulty.

The bypass hoses are attached to the EACV and fast idle valve which are located on the front part of the intake manifold. Throttle body is the part where the accelerator cable ends.