having a problem cooling my vette...info: 79 vette/350auto/ problem: overheats on the highway but not while driving around town..i have bought anew fan clutch/fan shroud(old one broken at the top half) in the process of buying a set of 11in. cooling fans...wonder if the fans will do the job and i can remove the clutch and fan or if i need them all..may have to replace the radiator as it seems to have been repaired in the past(3x4 in. spot in the middle of rad. looks repaired)...just bought the car and nevere owned a vette before...it seems to be an enigma..car titled as 79 (VIN in correct place and doesn't look tampered with)but has 80 body and the motor build is OCT30.'80...any ideas?title was original not salvage..give me your thoughts on any subjects..most appreciated.....Russ

 

Hey Russ,
First off, Welcome to CF.
Now,...... you can add all the fans in the world, that won't do it.
Generally the prob is bad thermo, clogged rad, blocked air intake, and what gets over looked the most is a weak hose. A weak hose will collapse at higher rpm and block water flow and cause over heating. (Generally while crusing at highway speeds. In town you are in and out of the throttle and the hose won't say collapsed.) I would check this first. The hoses should be firm and not squishy. This is my best shot.

 

c3 starship- thanks for the advice..the upper rad hose is in great shape but the lower one is a little mushy,but it has springs in to keep it from collapsing..i will replace it anyway.. i have already replaced the thermostat with a 180deg. i would still like to get the fan off the front of the motor and free up those couple of horses, do you think the elec fans would suffice if they wer'e activated at 180 and off at 170? man i love this car, black on black........air filter is new, car is carbed and pretty much stock-a/c is off the car..any help is greatly appreciated....thx-Russ

 

Hey Russ,
I'm a little stumped, normally a car will overheat in traffic. How does the water look? Any rust? You could try flushing the system. Since your hoses are o.k., and you've changed the stat, my next shot is the rad. The repair says to me that all ain't right. Concidering the age of the car, it may be time to change it. Time is your enemy, crap will naturally build up in the passages. If you do a flushing, try Calgon dish washing liquid. We use it to clean our diesel truck rads all the time. Cuts oils and gunk. (I assume that the water pump has noleaks at all.) My '80 L82 had an overheating prob and I flushed the system. It did help, but I'm in the process of installing a 454 to replace a tired 350. I'm going to S$%t can the rad and go to high volume, deep core.

I'm with you on the elec. fans. I've been looking into the dual elec. fan set up. I'm going to go with this when I make the change to the 454.

ps, I'm sorry, by blocked air intake, I ment the air flow into the rad. Check the cooling fins. If they are bent over it will constrict the air flow. They can be straighted with a small scewdriver, but be gentle, don't break anything loose.

 

Hey Russ,
Man have I been there and DONE that............c3 has you on the right track, stick to that advice......i would offer up that you change to a 160 degree thermostat, and add "water wetter" to your radiatior(this can be found at most all auto parts stores, its pink so its easy to locate!)..........those two things made a DRASTIC improvement on my operating temp!

Good luck,
Kyle
`73

 

Hey Russ,
Are you having any luck with the cooling prob?
Don't let me scare you, but, any oil in the water or water in the oil?(a milky white goo on dip stick) Tryin' to run this down for ya.

 

My first thought is you have an airflow problem-assuming your hoses are in good shape. If it is indeed an airflow problem, an electric fan that is wired to freewheel at freeway speeds providing the temperature setting is right, can help alleviate that problem. High speed overheating is usually an indication of an obstruction meaning less heat transfer through the radiator surface. How old is your fan clutch? -Jabin

 

I am waiting for all my parts to get here (some from ebay)-gonna put a new shroud in-pull rad. and have it flow/pressure tested-install new lower hose and install dual 11in. fans on the pull side-have already tried water wetter but it didn't work that great-question for anyone out there---will the 11in. fans pull enough air so that I can remove the clutch fan completely? I think I'm gonna try this- I also have a 14 in. fan..Both fans came off of vettes-probably gonna flush the block also...sucks to not get on the freeway with the tops off and cruise to the mountains!!!!!!!! I will keep you all posted as things go along....Thx for everyones help....

 

Yes, the twin 11's will replace the original clutch fan just fine, but they will not solve the over heating prob you have right now.

 

Without getting into the thermal dynamics of compressed fluids (I can if you want...), suffice it to say that a large, single fan will provide more RPM speed and thus a much higher level of heat transfer than going with dual fans. The Mark VIII fans fit exactly into the radiator fin area of 3rd gen. Vettes in the 4spd cars and cover 95% of the fin area in the automatic equipped cars! The fans measure 19x22x5.75 and pull 5000 CFM by way of an 18" fan (encased it its own shroud) and it is the most powereful fan you can buy on the market-OEM or aftermarket. We equip them with Spal PWM controllers and offer 70-amp HD relay kits to serve as an over-ride feature if so desired. If you find it to be a lack of airflow, that is the best solution but you have to rule out everything else first. I build these kits for road course 1st gen. Camaros too so I know they can handle whatever anybody can throw at them. Let us know whatyour results turn out to be! -Jabin