FCme

hi all, boring question for ya .My water temp gauge is not working, I was just wondering is it the coolant sender under the oil filter or the wter temp sender on the water pump that gives the reading on the gauge ??? which one sends a value to the ECU ???

Also my alt belt snapped and the alt wheel was extremly hot , as well as somthing draining the bat. Are these probs related ???

Thanks for any help in advance

89 Rag

The one under the oil filter sends it to the gauge, The ECU reads the other, and there's a third, for level, in the top of the radiator.

Baldy

How's your voltmeter been reading lately?

FCme

How many wires should be coming off the water temp sender cause it's been cut and joined twice ??? so if I buy an after market water temp gauge, the new sender goes in under the oil filter ???

no volt meter on the car man

thanks for the help

89 Rag

Its a strange pipe thread that the stock gauge sender screws into, most aftermarket's don't offer this correct size, and if I remember correctly an adapter fitting is not an easy find either. You could tap it to the aftermarket size, which I wouldn't recommend, unless the engine was apart already, or put a new stock sender unit back in and wire it correctly, (only one wire) with a flat blade connetor on the end.

clokker

The stock sending unit is a British pipe thread, it differs from normal pipe thread by one thread per inch.

Basically, a normal sending unit with standard pipe thread will work fine in the stock hole.

89 Rag

British pipe thread it is, however it isnt an exact fit, and the hole is tapered. What you are suggesting is forcing something that doesn't fit, unless using the stock Mazda sending unit.

clokker

No argument from me.

However, the VDO sending unit I "forced" into that hole has been fine for over a year.

YMMV.

89 Rag

Ok, i'll bite.



There is no maybe about it, forced is forced. And being that the plate threads won't give, the sender unit threads will (because they're made of softer metals) which means the filings of these threads breaking off are intoduced into the internal portion of the engine via the cooling system.



Why would that be a potential problem?



The cooling system, that is pressurized, has no filter in the system so those filings are allowed to make thier way anywhere the coolant flows. Will they fall harmlessly to the bottom of the radiator or get stuck along the bottom of the plates and housings, maybe, but if they don't they get to run through; your turbo, into your intake manifold via the throttle body ultimately ending up IN your engine, (metal filings in the combustion chamber = bad) or land against any of the sensor ends that penetrate the cooling system in various places.



You wouldn't port an engine or manifold with it still bolted together, would you? Just because you lucked out and havent seemed to suffer any consequences doesn't mean someone else might on the opinion of bad advice.

clokker

Given that the stock unit has tapered threads, it's "forced" by design during installation also.

Even the stocker only screws in about 5-7 threads before the taper wedges it, just like the "incorrect" aftermarket part.



Yeah, I'd prefer a perfect match too, but IMO, the aftermarket sensors can be installed without undue concern.