High Engine Temperature in Traffic - my solution.

[Bruce]

Hi People of ZR1 land.
Ive been concerned with the very high engine temperature when the car is in slow traffic or in town stopping at lights etc. I saw temps up to 118 degrees (as seen on the DIC) when stopping at lights or just driving through town slowly.

I know the radiator has 2 fans. I read somewhere that one is a primary and the other a secondary unit. Seems they dont come on at the same time and I doubt if the secondary one has ever come on. (a bit hard to check at the stoplights!)

Soooo I thought Id manually operate both fans to see what difference this made.
I hooked up a simple toggling remote control receiver in the engine bay with steering diodes connected to both fan relays. I can now operate the fan relays from a small hand held remote inside the car. I did this so I wouldnt have to bugger about putting a wire through the firewall and then to a switch somewhere - and to test my theory without too much effort.

Wow - what a difference. I have found now that if drive around town, I just switch on the fans and leave them going. Temperature never goes over 94 now, air con going, stop start traffic, hot day etc. Obviously when I get out on the open road Id turn them off. As my switching device is paralleled with the existing ECM, the ECM can still switch on and off the primary fan etc.

I'll probably consider looking for a decent place to put a small switch (possibly by the drink holder next to the ciggy lighter socket) then I can operate the fans as needed.

All this could be done from the ECU but I dont have the programming equipment etc. I could make up some sort of simple control using a Raspberry Pi or similar, or even some sort of discrete component system but I think Id just be happy with the simple switch. I think its something that us ZR1 owners tend to keep an eye on the temperature gauge so its not such a biggie to operate the fans manually.

[efnfast]

I think most of us here would highly recommend Marc Haibecks chip, it will turn the fans on sooner and massage a couple other things.
http://www.zr1specialist.com/index.html

[We Gone]

I went the switch route years ago on my first ZR1, than moved on to Marc Haibecks chip. Just one less thing to worry about. Never see temps over 210f.

[lfalzarano]

Go with the chip for cooling and performance.


Sent from my iPhone using ZR-1 Net Registry (http://r.tapatalk.com/byo?rid=90383)

[BigJohn]

At 118 degrees your thermostat will still be closed!

[Bruce]

Morning all.
John, 118 degrees celsius is 244 fahrenheit so the thermostat is well and truely open! It was an experiment that cost me nothing as I had the stuff sitting around the workshop. I might look at a chip change one day but for the moment, its one of 6 cars sitting in the collection so the cost might not make it viable at this stage as its only driven perhaps once a month. :)

[BigJohn]

Callaway put in an oversized radiator and larger oil coolers in my car.

[diamond zr1]

for a larger man a larger radiator and larger oil coolers is the right thing to do

[Dynomite]

Ive been concerned with the very high engine temperature when the car is in slow traffic or in town stopping at lights etc. I saw temps up to 118 degrees (as seen on the DIC) when stopping at lights or just driving through town slowly.


The trick is to keep rpms above 2,000 rpm simply because the water pump is not pumping enough coolant at rpms less than that.

See Item #5 Thermostats, Fans, Radiators and Coolant Filling (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-6.html#post1584987828)

Just a little new trick to solve the Air Locked Water Pump easily.
I fill with Coolant/Distilled Water. Then the BIG Secret......
A. I use a vice grips and close off the coolant to the Plastic Overflow under Passenger Headlight.
B. I fill Black Coolant Reservoir in front of passenger side window and when the bubbling stops.....Blow into/pressurize that Reservoir holding pressure for about 10 seconds. More bubbles will come from the top of the radiator hose. I refill with Distilled Water and Blow into/pressurize the Coolant System again. I repeat this maybe three times until no bubbles come back from the top of the Radiator. I then replace the Coolant Reservoir Cap and remove Vice Grips.....and fire up the LT5 keeping a hand on the Injector Housing Coolant Manifolds to assure they get warm within a minute. (That Happens with this method of Coolant Filling 100% of the time).

With this procedure you are pressurizing both sides of the radiator but with each pressurizing cycle more coolant is being pushed into the coolant system and more air is bubbling out from the top of the radiator.

[Bruce]

Dyno, sounds like a good thing to be doing. I did the usual 'keep a few revs up when sitting at the lights' etc thing, so the pump can circulate more water - certainly helps drop the temperature.

I often wondered how they did the water filling on the production line, afterall they only had like 90 seconds at the filling station to get the water in the engine and I assume it was filled with no trapped air?

Ohh speaking of such things - does anyone know how they do the brake fluid filling and brake bleading on the production line? Again, probably only 90 seconds to get this done. Anyone know what the procedure is they use or how they do it?

[WARP TEN]

I will certainly second getting Marc's chip. I had one in both my earlier '93 and my '95. Worked great to control temps. However, there is one thing you should not forget and perhaps check. The C4s are "bottom feeders", meaning they pull air for the radiator up from below the front nose of the car. As a result, they also pick up a lot of sand, dust, debris, leaves, etc. Overtime, the fins in the radiator become plugged. When I first had an overheating problem with the '93, with about 40k miles on it, I had the radiator pulled out and it about 40% clogged. (Marc said he once removed a radiator and got about 20 pounds of sane out of it) Hosed it out to clean all the fins. Then installed Marc's chip and it worked fine ever since. It is often difficult to really see if the radiator is clogged while installed (I know Marc has a way to view much of it) so it seemed best to just remove it when I ran into the problem. The '95 was low miles and was not clogged so I just had Marc install the chip. --bob

[G-Sting]

Morning all.
John, 118 degrees celsius is 244 fahrenheit so the thermostat is well and truely open! It was an experiment that cost me nothing as I had the stuff sitting around the workshop. I might look at a chip change one day but for the moment, its one of 6 cars sitting in the collection so the cost might not make it viable at this stage as its only driven perhaps once a month. :)

Greetings Bruce,

Might there be a way of posting some nice ZR-1 pics with that epic New Zealand landscape in the background? :-D

Cheers,
'G'

[USAF Retired]

Try cutting the Radiator Shroud to allow direct cold air flow entering the engine?

[BigJohn]

No No No!
Let's not start cutting up the car.

Fluid levels up to snuff, clean radiator and still over heating!