Colder thermostat

[c4_4me]

I have a 84 z-51 with the 4 plus 3. I installed a 160 degree thermostat in it to help with the temp when running in town as it would climb to 240 degrees then the fan would kick in.
The problem I have now is the over drive shuts off at 177 degrees and that is about where the car runs going down the road.
My fan works in the car but I have been told that even tho it works it may be getting tired and not running as fast as it should, so it won't cool correctly. Or do I need to install a colder sensor in it so it turns on earlier? Or is there a way to lye to the computer so the over drive will stay on. I have noticed that even with the colder thermo in it it still eaches 220 in town...... My question is what is the safe thing to do here???

 

[vetteoz]

I have noticed that even with the colder thermo in it it still eaches 220 in town......

Lower stat temp only changes WHEN the thermostat opens; meaning it takes longer to warm up .
Once hot ,at low speed or in traffic running temp is dictated by the fan ON temp which you didn't change
Some light reading
http://www.corvetteactioncenter.com...mance/49862-thermostat-poll-160-vs-180-a.html

would climb to 240 degrees then the fan would kick in.

First thing you SHOULD have done is put a new fan switch in ( or checked the old one was working correctly your temp gauge may be wrong , not uncommon )
to operate the fan at the correct factory temp (228F? ) instead of changing the thermostat
What you should do now is change your fan switch to a lower one WITH a 180 thermo so the engine runs at higher temp but fans come on sooner

 

[Hib Halverson]

If your engine is running hot in traffic, a 160 thermostat will do nothing to solve that problem.

What you need to do is fix what is causing the cooling system to not work properly.

Make sure your front air dam is in good condition. Inspect the area in front of the radiator and between the hvac and the radiator for any debris that may restrict cooling air flow. Verify that the coolant flow through the radiator is not restricted.

Test the cooling fan system per the Service Manual to make sure it is working properly. As "vetteoz" suggests, check to make sure the fan switch is operating correctly--if the fan kicks on at 240 instead of 228, there's a problem--and that the temp. display is accurate.

Once you've addressed all that, sell the 160 thermostat on eBay and install a 180 deg 'stat.

Good luck.

 

[Bronze85]

According to my gages the main fan turns on at approx 190 degrees and the auxillary fan comes on approx 228 degrees. High engine temp in traffic is usually due to insufficient air movement over the radiator core, conversely hi temp at highway speeds indicate a coolant flow restriction.The main fan is controlled by the ecm and the aux. has its own temp switch/sensor.

 

[Rodney Gold]

I would just like to know if this is normal for an 86 L98
On open road the car runs at 80 degrees C on a cool day - not much more than 85 on a hot day
(178 - 185)
The fans come on at precisely 101c (215F) and go off at 91c (195) in stop and go or traffic
Car has no cat and none of the emissions stuff going into the exhast manifolds

 

[BADDUCK]

Sounds like the fans have been re programed. Those are not factory on/off temps at least in the USA. However, your car is doing fine.

Be advised your fans may turn counter clockwise south of the Equator.

 

[Rodney Gold]

Ta for the reassurance
I noticed something was amiss when one day the doors wouldnt open after I put the heater blower on , I really struggled to break the suction.
Worst of all , when the car landed here it had a 4 speed overdrive reverse and only one forward gear

 

[TedC]

180 in a L98 is the recommended replacement direct from Gordon Killebrew. 160 is too cold and 195 is too hot. 195 mandated for emissions. Anything below 180 requires ECM changes. At the time I asked Gordon, my question was specific to L98s, not cross fires. But it sounds like 160 is too cold for your setup.

 

[BADDUCK]

Ta for the reassurance
I noticed something was amiss when one day the doors wouldnt open after I put the heater blower on , I really struggled to break the suction.
Worst of all , when the car landed here it had a 4 speed overdrive reverse and only one forward gear

That would make it a French car!

 

[roger longman]

That would make it a French car!

Or Russian!....

 

[c4_4me]

Hey all thanks for your thoughts.... This is the first hobby car I have had that is computer controlled and am not totally comfortable with this stuff yet...... radiator is clean and air dam is perfect. I do have a hypertec "thermo king" chip that I can put in as it calls for it in the directions. I have heard bad things about this chip, hence why I haven't put it in. I will check out the sending unit for the fans tho.... Thanks for your time and sorry if I sound ignorant, I am not.....

 

[Rodney Gold]

I'm in the same boat C4-4 - my last vette was a C3 and I know plenty bout old school stuff - this computer stuff is a little confusing to me - Im getting an OBD1 cable to attach to my laptop and have downloaded some logging/diagnostic freeware for my C4 and hopefully will get a little more into it all.

 

[vetteoz]

.The main fan is controlled by the ecm and the aux. has its own temp switch/sensor.

Except in '84 which only has a mech switch for the main fan ,carried over from the C3's