Is my water pump going out?
 

Hi,

I have a problem with my 1996 VVT swapped and Rotrex equipped MX-5.

The car is running fine when there is no load on the engine. As soon as I get some load on the engine the car starts to get hot.

I can drive around with light load and get water temps of 93-94°C (199-201°F), as soon as I get on the throttle a bit more or if there is a hill I drive up or something like this the car starts to get hot up to 98°C (208°F) (this is where I usually get of the throttle to keep the car from overheating)

If I go back to cruising again, temps get back to normal values very fast...

I did 2 times a 450km drive with the car on the German Autobahn driving 160km/h (100mph) for an extended period - where I could keep the temps in check with just going into cruise mode when the temps were rising...

First thought was the thermostat, but this seems to be fine. Could my water pump be going out?

Thanks for your help and suggestions.

Water pumps usually leak when they fail.

208 doesn't sound all that hot, but I'm assuming it didn't used to do it? A car that overheats easily when you start using lots of power sounds like a head gasket failure to me. I'd do a leakdown test and see what it says.

--Ian

My guess is radiator is 15mm thick, dirty on the inside, and old.

50mm core, aluminium, new...;-)

Well that guess was wrong then. :)

I doubt it's the water pump, when they die they usually leak, not stop pumping.

What is your fan setup/shroud on this radiator? What brand radiator?

Dual spal fans 1300ccm (?) with shroud on IL Motorsports (China) radiator.

My guess is coolant re route and trapped air on the head ...

No reroute yet, but if it turns out that it is the head gasket I guess there will be a 99-00head gasket and a coolant reroute.

Opinions are more towards a head gasket failure now. I will re-check my fan setup and radiator and then maybe check the head gasket.

I had a ground problem to my OEM coolant temp sensor before I added the Rotrex and the fans were not working, I thought I realized this early but maybe the car got too hot and killed the head gasket. Though I don't have a lot of coolant loss or white smoke out of the exhaust ect.

Mine was a faulty thermostat. Cheap and easy to try another.

Yeah, I will try that first, cheap and easy - then go eventually go on to the more expensive and difficult parts...