Hey guys, Bought my daughter a 92 camaro RS. It has a 305 and everything is stock. My problem is that when the car is in stop and go traffic, the water temp redlines. The fan will come on at about the redline mark and will cool it to about 230. within three minutes of idling it has redlined again. I have changed the thermostat, the fan switch on the passenger and driver sides. The gauge appears to act funny at times. It will jump 30 or so degrees in just a few seconds. So i took a after market gauge drop it in the radiator, let the in dash gauge redline. The after market gauge never read above 210. I also borrowed a laser temp gun from work. I shot the water neck, incoming and out going radiator hose, the block in many different areas and the rad itself. All the reading were between 180 and 240. I assumed it must be the gauge. My biggest concern though, as the gauge climbs into the red I get a little vavle chatter on accelleration. Witch teels me something getting to hot. I turned the timing a little thinking it was set to high. made no difference. I have tried all the inexpensive stuff I can think of. if you guys have any ideas it would be greatly appreciated.
Thanks, Randy

 

Is it dual fan or single fan? if dual, sounds like the primary fan isn't coming on. What temp stat did you put in? Stock is 195, I like 180. Stock fan switch comes on around 220, I put in a Jet fan switch, on at 200 off at 185. This stat and switch combo seems to work really well. Reset the timing back to 6 btdc with the ESC diconnected. Someone else can give you more detail on checking the fan operation. Good luck

 

She has a sinle fan and currnetly has a 195 thermo. I will try a 180 this weekend.I am considering a adjustable fan switch I was reading about on the board. I'm very good when it comes to the mechanical end of a car. Though I lack considerbaly on the electrical end. If anyone has any thoughts, I am listening. She gets her drivers liscence in june. I still have a little time. just wanna make sure its right when she begins to drive it. lord knows I don't wanna blowed head gasket or worse.
Thanks, Randy

 

a fan switch for an 87 T-type/grand national will turn on the fan at 215-220 and off around 200-205, so it will work with a 195 t-stat, I am using one in my 89 along with a 180 t-stat and my temp never goes over 220 in traffic and it stays around 185-190 on the freeway

 

Thanks guys. Youv've been l aot of help. She gets her liscunse in June. Just trying to make sure she's in good shape, when she gets them. May be a week or so til I attempt to solve the problem. When I do I let you guys know what fixed it. Best part is I'll need to drive it for a week or so to make sure everything is O.K....hehe...She does'nt care anyway.
Thanks, Randy

 

Hold the phone Randy. You are right, if you are getting engine noise or clatter it IS getting too hot. The guage sender is the one on the driver side between cyl 1&3, the fan switch is the one on the pass side around cyls 6&8. Based on what you say about the very rapid temp rise I would suspect another issue. The only thing that would cause a very rapid temp change would be depressurization of the cooling system. First is it losing any coolant. Fill the recovery bottle to the cold line then try letting it run through a couple of heating cooling cycles. Is there any coolant loss? Look at the oil. Is it a little milky? A very common problem is the intake manifold gasket, they tend to break down around the front where the coolant passage jumps between the cylinder heads. After it's hot when the engine is off can you hear any hissing around the intake indicating loss of pressure. If thats OK try a new rad cap, if its getting funky it may be releasing pressure prematurely. Did you replace the fan relay? They are notorious for getting intermittent. The relay contacts burn and become misaligned causing erratic operation. If you have not changed it replace it no if's and's or butt's. When system pressure is lost when an engine is hot the coolant will superheat in the cyl heads where the guage sender is and even a laser check at the rad may show a near normal temp. Also, another common problem is the lower rad hose collapsing causing very fast restriction of the coolant. Get one with a spring reinforcement. Modifying the cooling system will not fix what I and you suspect is going on. I just turned my daughter loose on the road and the last thing you want are phone calls at midnight. Keep us posted, Dan

 

I have to second the idea on the intake leak. Mechanic showed me one of the gaskets on my 305 & it has actually disolved some, but it was at the back rather than at the front.

 

Thanks for the ideas. I'm noy very good on electrical parts of the car. I got a friend who checked for the resistance coming from the sensor to the gauge. He said that the readings were fine that the problem is the gauge. He stated according to the readings it was coming on around 230 and cutting off around 210. the gauge was reading 280 on and 250 The possible spark knock issue concerns me a tad though. Car runs great other than that. Oh yeh the O.D in the tranny goes in and out wat to much. Sometimes 4 or 5 times in a 3 or 4 second time period. No matter what i do it still happens.(with the throttle). Thanks guys I have learned more than I really wanted to know about the cooling system on that car. LOL
Thanks, Randy