Why Does 1985 CRX Now Run Hot with new Water Pump?
 

Why Does 1985 CRX Now Run Hot with new Water Pump?

I just had my timing belt & water pump replaced by a mechanic on my carbureted 1985 Honda CRX HF.
The water pump is by Aisin & timing belt by Gates.

I had absolutely no issues before & until after installing the timing belt & water pump. In other words it never ran hot.
However, it now runs very hot & up to the max line.

Note: The air conditioner works & the fan blower works, but the heater does not appear to work as I feel no heat.

Mechanic says if there is no heat coming out when both the heater & fan are turned on-then it typically indicates the water pump is not circulating. Is it possible my mechanic overlooked something?

Any suggestions on what I should test or do?

The mechanic replaced the thermostat, which really slowed down the engine from heating up when parked. However it still gradually climbs towards the max line or max temp, just not as quickly as before.

The engine cooling fan does not seem to work either.

The mechanic seems to think its the Aisin water pump. Your thoughts?

I'd try bleeding the cooling system before tearing it apart again. A pocket of air could be blocking the flow of coolant. There should be a bleed screw on the engine, near the upper radiator hose.

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Did the water pump come with a plastic plug in the suction side?

Was a rag or paper towel used to keep the hoses from dripping when they were disconnected?

If so, it's possible that the mechanic didn't remove the plastic plug and or rag.

It's also possible that the radiator is full of gunk on the inside, not allowing it to
circulate.

If so, replace radiator...


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After a heat up/cool down, open the radiator cap. If it's not full to the top, fill and repeat. If the coolant level in the overflow tank drops after a heat up/cool down, there is still air in the system.

More questions for clarification...
 

Thanks for replying .

I saw the mechanic do the air bleed, but for some reason he seem surprised the bleed valve did not appear to work... no matter what how far he adjusted it.

Should he have felt any air coming out? If not, then what should he check next?

Does the waterpump housing have a weep hole to indicate its bad?

Could the water pump still be installed even with the plastic plug in the suction side? & would the mechanic need to remove the timing belt attached to water pump in order to access & remove the plug?

Do you believe reverse flushing the radiator with a garden hose be effective to clear out any blockages?

Yes.

Here's More info I discovered for Diagnosing Issue...
 

1. Should the fan motor run continuously when AC is turned on? It runs intermittently on & off.

2. After warming up engine, the fan motor does not come on when AC is turned off.

3. Does this indicate a defective fan motor or Thermosenser?

4. Note: The top radiator hose gets warm, but not the bottom house. What does this indicate?

Furthermore, when the mechanic loosened the air bleed bolt, absolutely no coolant ran out even with radiator filled.

5. I'm still not getting any heat from the heater.

I think a blockage might be indicated, given what you describe about the air bleed. It does not sound like much or any coolant is circulating.

Every car I've ever worked on that did that was a stuck thermostat.
A few have responded by tapping on the thermostat's housing. I would still change it if that worked.
You could take the thermostat completely out to eliminate it as the blockage.
did we try a new thermostat?
I've seen plenty of new and used thermostats which are just stuck closed.

1. Should the fan motor run continuously when AC is turned on? It runs intermittently on & off.?

That's weird.... Every car I know of keeps the fan on for ac, some modern ones turn it off at driving speeds, but that's an old car, that ive never worked on so i have no clue.
But in general, you need it... Its possible for the evaporation to not fully happen, which allows liquid to enter the compressor, then its ghandi. A fan keeps it efficient enough to prevent this. But on most classic modern cars with a single fan, you have a high and low speed, which can be fed by up to 3 separate circuits. IE, low for ac, low for say 190-210°, high for ac + 190+°, high for 230°+ etc. Edit: I forgot to mention, trans temp can kick it on, on some cars.

That's a question for a honda forum as far as the fan speeds IMHO,
but I vote for checking for the plug in the water pump, testing/replacing tstat, and back flushing the cooling system just because its gonna get drained anyway. I also would go for some real acid like CLR for the cooling system, just because some old cars have electrolysis type corrosion going on, and it just needs to be done, especially with aging wiring etc. Its all over my head, so I just flush annually..... But I get results in the drain pan, so its something to do with my sensors and grounds drawing or creating a current. I'm not a science doctor, but my coolant creates deposits. Yearly.