1967 427 Overheating Waterpump

[Sal P.]

Does anyone know the date of the article written on the specialty waterpump that helped fix the problems with overheating? Or does anyone have a recommendation for waterpumps you have replaced.

[Kent S.]

Re: 1967 427 Overheating Waterpump

If you're not concerned about "correct" I've used FlowKooler waterpumps on several non-NCRS cars. Best you can buy - Summit, Jegs, etc. all carry them.

[Joe L.]

Re: 1967 427 Overheating Waterpump

Does anyone know the date of the article written on the specialty waterpump that helped fix the problems with overheating? Or does anyone have a recommendation for waterpumps you have replaced.

Sal------


Generally speaking, big block overheating problems are not due to a waterpump problem. With big block (or other) waterpumps the primary failure area are coolant leakage or bearing failure. Either are readily identified as such.

[Mark F.]

Re: 1967 427 Overheating Waterpump

Does anyone know the date of the article written on the specialty waterpump that helped fix the problems with overheating? Or does anyone have a recommendation for waterpumps you have replaced.

Sal,

Perhaps you can help us by refining a few more details about your problem.


If it is a '67 BB and the radiator is boiling over, mine (L68) would boil over when up to temp until I figured out (and was advised by those more knowledgeable than me) that I was overfilling the radiator. I was always taught to bring the coolant level at least up above the top-most radiator copper fins visible with the cap off. That apparently doesn't work for a lot of BBs (at least not mine). I added water wetter to my coolant and let the top 2 or 3 rows of internal copper waffle fins rest above the coolant level (they are slanted hi at front lo at back) . Mine has not boiled over since doing that 20+ years ago...your mileage may vary

[Duke W.]

Re: 1967 427 Overheating Waterpump

I'll add to the above:

1. Is the engine "stock" or modified, and if, so, how?

2. Under what conditions does it "overheat"? Around town in traffic? Highway? Describe in detail including actual gage temp readings and IR readings at the upper radiator hose and radiator inlet nipple.

3. Measure and report idle vacuum at SPECIFIED idle RPM., like xx" Hg @ yyy RPM... in neutral if a manual trans or DRIVE if an automatic.

4. What is the "ID" stamped on the VAC mounting bracket, and if you have a vacuum pump, how much vacuum does it take to start the pin to move and how much does it take to pull it to the maximum available movement.

"Overheating" threads are common, but few give enough data to effectively troubleshoot. Most responses are just guesses, which are basically worthless and can just get you chasing your tail and swapping parts for no rational reason.

The three most common causes or "overheating" or hot running are:

1. A dead VAC or ported vacuum advance or insufficient initial timing.

2. Dead clutch fan.

3. Insufficient radiator heat transfer capacity due to either an inadequate (non-OEM spec) radiator or internal deposit build up that reduces heat transfer efficiency.

Answering all the posted questions will help the TDB zero in on a likely cause(s) and point you in the correct direction to effect a repair.

Duke

[Mark E.]

Re: 1967 427 Overheating Waterpump

Agree with Joe- the pump is doing its job if it isn't leaking, wobbling, or making noise. If the car is over heating, check ignition timing and cooling system. Is it clean, radiator not clogged (inside and out), shroud and seals intact,
fan clutch working?

BTW, boiling over is different than the radiator cap releasing pressure. Boiling over (not normal) is when coolant boils in the engine, which can cause the cap to release. It is normal for the cap to release coolant and/or air to accommodate coolant expansion as it heats up. For cars without a coolant recovery system, coolant will puke out over several heat cycles until there's enough air in the system to accommodate coolant expansion.

[James G.]

Re: 1967 427 Overheating Waterpump

90% of overheating problems I have dealt with on Corvettes (equipped with Clutch fans) have been remied by rebuilding the fan clutch.

If the fan blades make more than one complete revolution after the engine stops... the clutch needs to be rebuilt.

[Richard M.]

Re: 1967 427 Overheating Waterpump

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