I own a 96 z28 Camaro I had your oil changed in it about 2 weeks ago my check gauge lights came on they my service engine light came on my temperature gauge is acting a little funny I reset everything behind doing the battery for 30 minutes now cars running a little hotter than usual yeah I'm noticing that my fan won't kick on unless I turn the heater defrost on but what's stomping me is if I'm sitting at a red light if my car is in neutral or park and I give it gas temperature gauge will drop down below the halfway mark anybody have any suggestions on what this may be

 

How high is the temp gauge BEFORE you increase the RPM? Increasing RPM causes more coolant to flow through the engine. A small drop in temp wouldn’t be unreasonable. Depends how high it is BEFORE you increase the revs.

 

The the last line before the red I want to say 240 maybe sometimes even a little below that and when I give it gas it'll drop just below the halfway mark

 

Here's the way the system is supposed to work with stock PCM programming:

- The system is designed to run in the middle of the gauge, about 210-degF.

- When the coolant reaches 226-degF, the 95-97 fans turn on at low speed.

- When the coolant reaches 235-degF, the fans shift to high speed

- If you interpolate the gauge markings, the line right before the red zone is ~235-degF

Appears yours is running excessively hot if it runs at the line before the red zone.

Does this problem show up mainly after cruising on the freeway at 50-60 (or higher) MPH? If so, check under the front bumper cover and make sure the plastic air dam is still in place. If the dam is missing, as speed increases, air flow from under the nose of the car, up into the radiator drops dramatically, and the engine can overheat. When you come to a stop, the heat load on the engine drops, and there is enough air flow without the air dam.

You indicate the cool down occurs "sitting at a red light if my car is in neutral or park ". Putting the trans in park or neutral reduces the radiator heat load from the convertor. Is your converter stock or high stall?

And you indicate this problem only occurred after an oil change? Have you checked the oil level?

Not likely the problem, but check the single wire that connects to the coolant temp sensor in the drivers side head, between #1 and #3. if it's loose, it may be affecting the gauge reading, depending on engine movement under load vs. in neutral. Or maybe they knocked the air dam off when they changed the oil.

 

Hey guys well after parking in my garage and screwing it for a little bit I came out and noticed a leak of antifreeze so I drove it around the block let it run for a minute and I watched the drip right above the water pump pulley it looks as if the drip is coming from the water pump so I'm thinking it's probably the gasket going to go ahead and put a new pump in I knew there was something going on though as it was running too hot thank you guys for all the info last post was very interesting to know all the info on the whole system appreciate that brother

 

There are “weep holes” in the bottom of the pump housing, to let out coolant that is bypassing the bearing. Be sure to protect the distributor from coolant when changing the pump.

 

Did the water pump take care of it? sounded like a low flow issue. the fans not coming on unless you're in defrost means the PCM is'nt seeing the same temperature the gauge is seeing. I cant remember if replacement pumps come with a new ECT sensor. if not, replace that too. Then your period and comma keys...