Overheating Problems

Question has come up enough that I need to put together a little help file for those who suddenly yell:

"Help, my roadster is overheating, what do I do?"

Is it really overheating?

If you can place your finger on the radiator and leave it there for 5 seconds it is just about 180 F. Dot your finger with a little saliva. Touch the radiator. If it evaporates, you are little over 210 degrees. If it snap, crackles, and pops you are OVERHEATED!

While different sender units will physically fit the roadster, the calibration may be different. So, if possible, follow up the above check my measuring the water temp with a thermometer. With the engine cold, remove the radiator cap [located on the engine on a 1600], and start the engine. Let it come up to temp, then insert a thermometer and measure the actual temp.

Reasons for over heating

A. Clogged radiator, or engine block?

Have the radiator rodded out at a radiator shop. Flush the cooling system, highly recommended to remove that block drain plug on the side of the block (just above the starter and near impossible to reach!).

Note 2000's have larger radiators, and are a drop in for a 1600 (with an extra radiator cap!).

B. Fan belt in good condition? Adjusted?

C. Compression test the motor, both when cold and hot.

Just rules out a bad head gasket (which is common overheating problems on 1600's).

D. Tune it up! Check and set the ignition timing. Do the centrifugal and vacuum advance function correctly? Remember too much advance, OR too much retarding, can cause problems.

E. Next set the valve clearance (should be done before carb adjustments).

F. Adjust the carbs. To lean can cause overheating. Check fuel pump is delivering enough fuel, fuel filter, and float levels.

G. Manifold and carb gaskets. Check to see if they are OK. Squirting WD-40 on them, while the engine is running, will help pin point air leaks.

H. Fan Clutch... almost NO roadster have those horrible OEM ('68-'70) fan clutchs on them any more. Still, with the engine off, see if you can spin the fan.

I. Distributor. Should have been spotted in item D. But if you have an original '68-'70 distributor that is timed at TDC, the vehicle is more likely to overheat. Fix is to buy the advance weights, cam, and springs for the '67 model and have them fitted. Then set the timing at 16 BDTC (SU's).

J. Too high of compression. Some 1600's with the heads shaved once too many times, and the original "pop up" pistons will have just too high of a compression ratio.

K. Engine block full of corrosion from years of abuse. Either J or K result in a engine tear down and rebuild.

Any and all comments on my write are appreciated. I tried to tailor this for our roadsters, but it is still generic.

What am I over looking???

I have also tried to keep the order in the most logical sequence based on "most common problem first". J & K are stretching it, but have found them "after everything else was done".

©1996, Thomas Walter