Mr.Luder

So my Prelude has been having this overheating issue for some time now that I can't seem to address. Both fans come on and I've replaced the thermostat, replaced the temp sensor on t-stat housing, replaced radiator cap, flushed and burped the cooling system but it still appears to be overheating. I can't run the A/C or it starts to overheat and the temp at times goes 3/4 to red while in slow moving traffic. What puzzles me is when I shut the car off and back on, the temp gauge returns to the center. Any ideas or anything else I should look and check? Car is a 94 Prelude VTEC w/ 201,xxx miles. Thanks in advance.

**UPDATE: So as I was driving this afternoon doing about 75 on the freeway, the temp went up to 3/4 to red and went back down to the middle. Does that say anything?

carnot

Is the car modified at all? It could be a faulty sending unit and I believe there is a procedure in the full service manual for checking. When the temp gauge reads 3/4 are the fans running constantly or do they cycle on and off?

Mr.Luder

The car does have a short ram intake, dc header and aftermarket muffler. No major modifications. I believe the fan cycles on and off. Sometimes the temp gauge drops back down after the fan cycles and sometimes it doesn't. It only does it when sitting at a red light for a longer period of time or in really slow moving traffic which leads me to believe that it actually is overheating unless the gauge is just getting the wrong reading period. Which one is the sending unit?

**UPDATE: So as I was driving this afternoon doing about 75 on the freeway, the temp went up to 3/4 to red and went back down to the middle. Does that say anything?

DCFIVER

You need to verify that the vehicle is actually overheating before continuing....

Thepowderblue

It should Never get that hot, Its overheating.

nemesis25

As stupid as this sounds, try running a new ground from the chassis to the valve cover and that should fix the issue you're having. Here is a little bit more detail about how I went about fixing my overheating:
https://honda-tech.com/forums/honda-prelude-4/small-problem-overheating-3062986/

fastbb2

I agree with nemesis25, I have the same problem with the car "overheating" but i have hondata s300 and it stays at a steady 192 degrees. replace the ground wire and you should be fine

SnlpeR

when was the last time you replaced the radiator?

minilogoguy18

You need to make sure the water pump is moving coolant and the fans are working, overheating at a stop then cooling while moving is normally a fan problem.

You need to quit throwing parts at it since you seem to have no idea what's wrong, you're just wasting your money guessing. Just because say something like the fan doesn't work doesn't mean replace the fan, there are other reasons why it wont work like wiring, thermoswitches or the relay.

Get a DMM and the manual and start fixing the problem before you waste more money on parts you don't need.