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I am trying to diagnose a couple of things on my project car and slowly cancelling out the possibilities.
When i re did the head gaskets i did not replace the water pump as it is well known that the v6 has a metal impeller and is really quite reliable.

Now my engine does get past 90 without either fan cutting in.
I have replaced resistors, relays, temperature sensor and wiring is good because when i bridge the relay the fans come on.

So my question is, if the water pump was faulty would this stop coolant from fully cycling through the engine to the temp sensor thus setting off the fans??
Also other than overheating what symptoms should be present if the pump has gone?
 

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Hi,well yor matal impeller my be good but shaft my be bad i had like this in past, shaft bin turning but impeller stys in place....ok so turn the engine,full hot air in con. allow engine to get worm for thermostat to open,need second person to rev.engine when u have to look in water trawel in coolant tank normally coolant will back with big pressure to the tank,if u have connected pipe to coolant tank even better dissconect pipe and rew engine if gib pressure pump is good if weak or no pressure pump gone...olso thermostat my stick touch pipe under radiator if top pipe is hot and bottom pipe cold thermostat gone,take thermostat out drop to boiling water check did cose tight if not thermostat folty,hope will help:)
 

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O yea and check cooling fan,they normally have two speeds,run engine and look at if second speed not kick in it will over heat engine i would say that fun busted(alots in Hondas all electric fans any way)
 

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.....or get an Infra Red thermometer & check the temperature of the hoses, radiator etc. Start from cold & check as the engine/water heats up.

Clive
 

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I spent ages trying to trace why my low speed fan was intermittent. The high speed fan worked normally but that comes on far too late for my liking. Like you, I'd ruled out the fan, resistors, relay, wiring, fuses etc. I'd ruled out the water pump because it was more than capable of cooling itself if it got a bit of air flowing through the radiator.

In the end, what got everything working normally was a new battery and all of the connectors cleaned. I can only assume that the ecu had got itself a bit confused and reset itself when the battery was changed.
 
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