hi i have a 88 toyota truck with the 22R carb engine that i purchaced about two months ago and now that it seems to get hotter outside the engine is getting hot but only when i go above about 55 it hasent got to the red yet but im sure it would if i diddint slow down but when i slow down or stop it cools ive replaced both radiator hoses ,thermostat ,radiator cap, flushed the radiator and timed it there is no noticeable loss of fluid and i can drive around town all day and it stays cool but the hotter it is outside the faster it gets hot on the freeway ive heard about drilling holes in the thermostat if you think this is the problem then please explain how to do this thank you.

 

does it actualy over heat? your temp sending unit could be going bad, if so i would put in a manual temp gauge.

 

it has got right to the red on a hot day and i slowed down about 1 minite after that it started slowly going down.

 

Try taking the spark plugs out one at a time and pressurising the cylinders with the radiator cap off. If it bubbles out of the radiator, then you have a cracked head gasket. My 85 did the same thing.

 

does anyone have any idea where the temp sending unit is?

 

Not sure on the 22R, but on the 22RE it is down on the head, by the intake, I think between #2 and #3 cyls.

I would suspect a partly clogged radiator, my 22RE did almost exactly as you describe. Any time outside temps were above 75 or so and speed over 65 it would start to run hot, temp gauge rising a few ticks. Back off the speed or wait for the air temps to drop and it ran cool. Put in a new 3-row radiator and it has run cool ever since (10 year now).

 

If it's in the budget, an infared temp sensor is a very handy tool. You can use it to measure the head temperature quickly and easily. You can use to to check rad hose temperatures too (see if it's cooling properly).

If the temps are comming down in slow driving, I'd x2 on the radiator being partially clogged. Unfortunately there's no way to verify this without replacing it.