Cooling Issue? Good thing?

Hey guys,

I recently noticed that driving this Saturday from Guelph all the way down to Ajax (exits 195 to 401), just as I get on exit 401 (Salem), my water temp gauge (stock cluster one) goes from normal operating temp and starts bobbing down, almost a few ticks over cold, then when I get to a complete stop at the intersection, it bobs back up to operating temp. At this time, I’m only running sleepy eyes (air coming in, cooling shit, etc). But sleepy eyes doesn’t exactly allow air to pass through the rad, just the air filter, and cool off whatever else is in the engine bay. But running at 120-130 km/h, it shouldn’t have caused too much of a drastic change. I’ve only been noticing it now… I’m not sure if its happened before… Basically, it only happens during long drives on the highway…

So this morning, I’m driving from Ajax back to Guelph. As I exit, I notice the same thing happening to the temp gauge. This time, I don’t only have sleepy eyes set, I’ve also got spacers on my hood hinges, raising the rear up about 1/2 to 3/4 of an inch. I did noticed that the rubber weather stripping is still there, so not a lot of air can escape that much from my hood. I’ll eventually remove the weather stripping after I get everything sorted… I’ve got no leaks in my water pump, or anywhere else in my cooling system (rad hoses, heater hoses, etc.)

Anyone have any ideas of whats going on?

I pulled over and checked my coolant overflow reservoir and its still at the normal height, just 2-3 cm’s below the MAX line.

I let the engine cool down for an hour, the coolant reservoir is still at the same height, and then I popped off my rad cap. The fluid level is still good…

Any ideas whats going on?


  • Mik

Ok there is a coolant temp sensor for the ecu and right near it is the the one to your cluster. Maybe you should take out the cluster one and clean it.

Happend to me, but my coolant temp sensor (beside the throttle body, not on the cluster) was shot so i just replaced that. I also noticed my thermostat was gunked up.
Changed that also and never had a problem…

What motor is this on btw? My situation involves the KA24DE.

might wanna try a rad flush.

Its got a KA24E.

As for the rad flush, its very likely that I’ll be doing that VERY soon, before winter…

The fluid in my overflow reservoir is dirty as fack… But the fluid inside the rad is still clean…


I noticed that whenever you bring the revs up, the needle starts to drop, but as the RPM dies down and goes to idle, it slowly goes back to either operating temp, or whatever the temp was before bringing up the revs…


I replaced the coolant temperature sensor with another one from my old KA. It was ok for the most part, but after a while it started doing the same thing. Now, its doing the exact same thing that the old coolant temp. sensor was doing…

Where’s the ‘cluster’ coolant temp. sensor? What’s needed to get to it/replace it?

It’s right beside the coolant temp sensor(ecu). It has a black clip hard to miss if you know where the CTS (ecu) is.

well from my experience a bad engine ground caused my temp gauge to act all weird.

sounds like your thermostat is stuck open