Packard Rod

My 1987 convertible has two cooling fans, one on the front of the radiator and one on the back.

The back fan turns on at about 160 degrees. The front fan never turns on, even with the air conditioning.

I have a Haynes Manual and nowhere does indicate a cooling fan in front of the radiator. I have added a switch under the dash to activate the relay that controls the front fan.

I get the added cooling when I think that it is needed but I still wonder what is supposed to really make this thing go!!!!!

rodj

Aux (front ) fan (RPO BP4 ) operates off it's own temp switch in the drv head and turns on at 238F, Not connected to A/c

If you main fan is running at 160 ( factory setting is 228F ) then either your computer has been reprogrammed
or someone has taken out the temp switch for the Aux fan and installed a lower temp one wired to run the main fan instead

As a note , the Haynes manual ,as you found out is only good as a door stop .
If you intend working on your car , get the Factory Service Manual (FSM )

Packard Rod

Wow! Quick and complete answer to my Corvette question....

Thank you so much..

I vote for the chip swap answer to the 160 degree fan operation. In working on this car for the past 6 years I have learned a lot. The CPU is labeled as re-manufactured and I suspect a new computer chip was installed at that time. I understand that there have been some issues with false check engine codes with the 1986 and 1987 year Corvettes and most if not all of the false code situations could be remedied with a chip swap.

I have just solved a long standing problem with a code 34 indicating vacuum leaks or Mass Air Flow Sensor problems. I replaced the MAF control and burn-off relays and all is well. This fix was initiated in part by this web site, so I joined as a freebe member. I see that you have been here a while. Perhaps I should pony up and help out!

I promise to "ditch" the Haynes Manual as it had no idea where the Control and burn-off relays were located. It was this site that told me to look behind the battery.

Thanks much
Packard Rod (1941 Packard street rod)

rodj

Have you got a 160 thermostat installed
Otherwise waste of time having the fan run at a temp the thermostat is closed at?
Places like Hypertech ( not highly regarded around here ) did reprogrammed memcals ( chips ) for the computer with lower fan temps to go with a matching lower temp thermostat

Packard Rod

Places like Hypertech ( not highly regarded around here ) did reprogrammed memcals ( chips ) for the computer with lower fan temps to go with a matching lower temp thermostat[/QUOTE]

The car runs at very reasonable temperatures. In cool weather the engine temperatures will hover between 170 and 180. With the AC on in 90 degree temperatures it may get to 200 degrees. This tells me that indeed a considerably lower temperature thermostat has been installed.

The original instruments (hard to read with the convertible top down) are still in operation but I have added instruments and gauges as follows: VDO tachometer, Speedometer, oil pressure and heat. I will try to post a photograph of that instillation in the near future.

The cost of a computer chip is not a problem. What is your recommendation as far as the best alternative?

rodj

Your operating temps are fine , was just that you said in your first post that the fan was running @ 160F?

SQUIRMIN VERMIN 84

As rodj said, get a FSM asap! Everything you'll need.

I found the Haynes and Chiltons manuals very useful!
When I have a car job that requires a lot of kneeling,
they are irreplaceable as kneepads! Soft, supportable and
handy paper to write down notes or soak up blood...