High coolant temp - ZR-1 Net Registry Forums

secondchance · 06-20-2010

I replaced my radiator (OEM) about 5 years ago and installed Marc's chip about a year ago and she had been running at around 213 - 215.
Last week in 90 degree weather in rush hour traffic I noticed temp gauge hitting 230. So, I turned off the AC and temp came down to 213 and as I drove home.
Yesterday (90 degree day), driving back from the body shop (yes, I got her back and she looks perfect!), driving 65 mph, temp was a 225. Normally, 65 in 6th gear use to be around 213 and a little cooler in 5th (better coolant flow I figured).
I will check for any debris on the front of the radiator and fans (been busy).
Anyone had a similar experience?

HIZNHRZ · 06-20-2010

Yun, with time and mileage (depnding on driving conditions) the conditions you are describing are what I experienced with my Red/Gray 91 fair weather daily driver. At the time the car was about 10 years old and had ~15K (very short commute to work) miles. I pulled the radiator and cleaned it and the car again ran cool again. If you saw what I cleaned out of the radiator fins you would have thought I drove the car at the beach. It was a very fine sand like material. It was almost more like dust than sand but the radiator was packed with it; especially towards the bottom. After cleaning it out, it was only about another year before the running unusaully hot conditions returned.

I pull the radiator again. Mileage was only another ~8K miles but the radiator was as loaded with sand/dust like material again that was very hard to see when crawling under the car or when looking from the top. This time I replaced the radiator with a Fluidyne radiator and thermostat. The car ran cooler than it ever had. It's only a guess but I'm thinking the stuff that loads up the radiator has something to do with the crap thrown on the streets in the winter.

I sold the car soon after. I do talk to the new owner. The car now has over 30K miles and the new owner has never brought up and cooling issues. The only other thing I can say is the stuff was very hard to clean out. I'm thinking as the open area aperture becomes restricted and it not only impedes air flow and cooling but it also loads back up again much quicker. I don't think it's your problem but I also have a 160 degree thermostate you are welcome to if you wanted to try it.

secondchance · 06-20-2010

Hate to admit it but I think you are right.
I drove this car after snow and all that stuff they sprinkled on the road.
I just checked Fluidyne but seems they no longer have one for corvette. Is fluidyne the wider one (racing application)? I hear Dewitt no longer offer one for C4.
Any recommendations - a good direct fit aluminum for street application?

thanks for the offer Scott. If I decide to try 160, I will call.

pantera1683 · 06-20-2010

Quote:

Originally Posted by secondchance

Hate to admit it but I think you are right.
I drove this car after snow and all that stuff they sprinkled on the road.
I just checked Fluidyne but seems they no longer have one for corvette. Is fluidyne the wider one (racing application)? I hear Dewitt no longer offer one for C4.
Any recommendations - a good direct fit aluminum for street application?

thanks for the offer Scott. If I decide to try 160, I will call.

There are plenty of replacement rads on ebay (china?), corvetterecycling (NOS great price), dewitts (they still make c4 rads), and others.

Aurora40 · 06-20-2010

FYI, if it was while cruising in 6th, try downshifting to 5th. If that brings the temp down quickly, it is caused by the low coolant flow at low RPM. It's a common issue that doesn't really have a solution (other than to downshift or drive faster).

secondchance · 06-20-2010

Quote:

Originally Posted by Aurora40

FYI, if it was while cruising in 6th, try downshifting to 5th. If that brings the temp down quickly, it is caused by the low coolant flow at low RPM. It's a common issue that doesn't really have a solution (other than to downshift or drive faster).

I know. She was running 220 in 5th. Normally, in 6th would run 213 and 207 or so in 5th.

secondchance · 06-20-2010

Those who are using Dewitt - are they better cooling relative to OEM? I remember reading fans have a bit of difficulty pushing air through - true?

GOLDCYLON · 06-20-2010

Quote:

Originally Posted by secondchance

Those who are using Dewitt - are they better cooling relative to OEM? I remember reading fans have a bit of difficulty pushing air through - true?

True thicker rad core

mine always runs cooler in 6th with a stock rad

secondchance · 06-20-2010

Mystery solved!
Rather than speculating I went for a test drive, noted it was doing the same thing - temp climbing even while cruising at 55 - 60.
Came back home, got on my back with a flashlight. It turns out that a plastic flap that is hung at the top of the radiator has to come down, tuck over the bottom of the front bumper and this is held in place w/ a plastic tab. It seems this piece has come loose and at speed this piece is piece is pushed back to the radiator. With both fans running, this piece get sucked towards the radiator further worsening the problem.
Hah! I don't have to spend a whole day wrestling with a radiator!

GOLDCYLON · 06-20-2010

You talking about the rain shield?

06-20-2010	#1
secondchance Join Date: Aug 2006 Location: McLean, VA Posts: 3,709	High coolant temp I replaced my radiator (OEM) about 5 years ago and installed Marc's chip about a year ago and she had been running at around 213 - 215. Last week in 90 degree weather in rush hour traffic I noticed temp gauge hitting 230. So, I turned off the AC and temp came down to 213 and as I drove home. Yesterday (90 degree day), driving back from the body shop (yes, I got her back and she looks perfect!), driving 65 mph, temp was a 225. Normally, 65 in 6th gear use to be around 213 and a little cooler in 5th (better coolant flow I figured). I will check for any debris on the front of the radiator and fans (been busy). Anyone had a similar experience?

06-20-2010	#2
HIZNHRZ Join Date: Apr 2004 Location: Germantown, MD Posts: 738	Re: High coolant temp Yun, with time and mileage (depnding on driving conditions) the conditions you are describing are what I experienced with my Red/Gray 91 fair weather daily driver. At the time the car was about 10 years old and had ~15K (very short commute to work) miles. I pulled the radiator and cleaned it and the car again ran cool again. If you saw what I cleaned out of the radiator fins you would have thought I drove the car at the beach. It was a very fine sand like material. It was almost more like dust than sand but the radiator was packed with it; especially towards the bottom. After cleaning it out, it was only about another year before the running unusaully hot conditions returned. I pull the radiator again. Mileage was only another ~8K miles but the radiator was as loaded with sand/dust like material again that was very hard to see when crawling under the car or when looking from the top. This time I replaced the radiator with a Fluidyne radiator and thermostat. The car ran cooler than it ever had. It's only a guess but I'm thinking the stuff that loads up the radiator has something to do with the crap thrown on the streets in the winter. I sold the car soon after. I do talk to the new owner. The car now has over 30K miles and the new owner has never brought up and cooling issues. The only other thing I can say is the stuff was very hard to clean out. I'm thinking as the open area aperture becomes restricted and it not only impedes air flow and cooling but it also loads back up again much quicker. I don't think it's your problem but I also have a 160 degree thermostate you are welcome to if you wanted to try it. Last edited by HIZNHRZ; 06-20-2010 at 11:55 AM.

06-20-2010	#3
secondchance Join Date: Aug 2006 Location: McLean, VA Posts: 3,709	Re: High coolant temp Hate to admit it but I think you are right. I drove this car after snow and all that stuff they sprinkled on the road. I just checked Fluidyne but seems they no longer have one for corvette. Is fluidyne the wider one (racing application)? I hear Dewitt no longer offer one for C4. Any recommendations - a good direct fit aluminum for street application? thanks for the offer Scott. If I decide to try 160, I will call.

06-20-2010	#5
Aurora40 Join Date: May 2005 Location: Leesburg, VA Posts: 2,713	Re: High coolant temp FYI, if it was while cruising in 6th, try downshifting to 5th. If that brings the temp down quickly, it is caused by the low coolant flow at low RPM. It's a common issue that doesn't really have a solution (other than to downshift or drive faster). __________________ Bob Saveland Former owner of #2517 [IMG]http://a.random-image.net/aurora40/vette.jpg[/img]

06-20-2010	#7
secondchance Join Date: Aug 2006 Location: McLean, VA Posts: 3,709	Re: High coolant temp Those who are using Dewitt - are they better cooling relative to OEM? I remember reading fans have a bit of difficulty pushing air through - true?

06-20-2010	#9
secondchance Join Date: Aug 2006 Location: McLean, VA Posts: 3,709	Re: High coolant temp Mystery solved! Rather than speculating I went for a test drive, noted it was doing the same thing - temp climbing even while cruising at 55 - 60. Came back home, got on my back with a flashlight. It turns out that a plastic flap that is hung at the top of the radiator has to come down, tuck over the bottom of the front bumper and this is held in place w/ a plastic tab. It seems this piece has come loose and at speed this piece is piece is pushed back to the radiator. With both fans running, this piece get sucked towards the radiator further worsening the problem. Hah! I don't have to spend a whole day wrestling with a radiator!

06-20-2010	#10
GOLDCYLON Join Date: May 2007 Location: Peoria, AZ Posts: 9,154	Re: High coolant temp You talking about the rain shield? __________________ GOLDCYLON - 91 ZR-1 #2014 GOLDCYLON - 90 ZR-1 #2794, 4L60e (Formerly Schrade's) GOLDCYLON - 11 CTS-V Arizona State Director 91 WHITE/BLACK #2014. 380 P&P&PCed,Ported Heads, Jeal Long tubes, Corsa Exhaust/FIKSE FM-5s /LED TLs, LED Headlights, Front Wilwood 6 piston narrowlite calipers and rear Wilwood caliper street shop mod,CNCed Coolant Pipes,TPI Cvr,Filter cover,Stainless Bolts, DRM/DOM PROM /ZFDOC mod build #102,DRLs,BMAD with stainless Debris Screen,Coplan Air Blaster, Pioneer APP Radio 4,Brey-Krause HB,Sub Bar,Fire extinguisher seat mount,DRM Coilovers,LEDs everywhere,Compass mirror (orange),V1 DIC hidden display, Homelink sun visor, Carbon Fiber top x3 and APSIS Carbon Fiber interior, APSIS CF Steering Wheel/NAPA Leather, Banski trailing arms, Guldstrand front suspension,urethane bushings from Prothane (total suspension) ZFDoc drive shaft safety loop, raptor shift light (orange),AO engineering louver front plate, Console seat cushion, 96CE seats with black custom Sheepskins, ss billet catch can,Viper remote entry/alarm,Cragar Rear Louvers,LED side louver lights, Dewitts Radiator with SPAL fans and a Woods 160 T-Stat 90 RED/BLACK #2794. 4L60e Automatic Stage V by RPM Transmission, TCI Dedicated TCM, OBX Stainless Headers, Corsa Exhaust, SAN Secondaries and Haibeck PROM, Exotic Muscle Coil overs, LED Interior Lights, LED Tail Lights, LED Headlights, 94 Sport seats with black custom Sheepskins , Cragar rear louvers, GS Front calipers, Banski Trailing arms, APSIS Carbon Fiber steering wheel, Front and Rear Baer Eradispeeds, DRLs, Guldstrand front suspension,urethane bushings from Prothane (total suspension), Dewitt's Raditor with Dual SPAL fans and a Haibeck 170 T-Stat 11 RED/GREY CTS-V