Yes it will help out at highway speeds. The seals make sure all the air goes through the radiator not over or around it.

 

If everyone doesn't mind I would like to get in on this issue. I am having the same problem with my 79. I just changed the clutch fan to the heavy duty/AC/L-82 unit, added the missing front air dam, and had the radiator cleaned out. Seals around the radiator are good. Although it take a little longer, it still heats up at highway speeds. From reading all the threads the only thing left is to change the bottom radiator hose with one that has a spring in it. Anyone have any other ideas that could help both of us. Thanks.

 

Lars, thanks for chiming in. I will look into my timing. I thought that might be a concern. I had a buddy put the motor in. Is it possible he set the timing retarded for break-in?

Mvisible, please let me know if that air dam works.

To the rest, I don't think Dewits fans/radiators use seals.


Good luck Mvisible.

 

UPDATE: We put on the air dam and it helped! What would happen before the air dam on the highway under steady normal acceleration the car would go to 250 in 1 or 2 min then would have to be kicked into neutral for the car to cool down, but now at steady pace doesnt go beyond the third line which is 230?

We also tested it under full hard acceleration and it did heat up to a little past 230 then once we layed off and went back to normal steady pace it cooled down on it own, which is better than before where we would completely have to put it into neutral. So yes the air dam did help! There is also did little open gap area where air would also get lost we are going to seal that up and we are thinking that it will direct air more efficiently. Will post pictures and update again once that has been completed.

 

You should jury rig up a secondary temperature sensor temporarily just so you validate what the one in your car is telling you. I've seen them be waaaaaay off.

 

Mvisible, Congrats. Still seems to run warm but at least that sounds like it helped a lot. Can't wait for mine to come in so I can install it.

Two more sugestions.

Switching to synthetic oil may show a small improvement

And how about getting the hot air out of the engine compartment. My engine bay is very warm because I can't get the hot air out of there. If I can find a cheap manometer I will check the pressure on the inside of the wiper cowl. If it is less then the pressure inside the engine compartment I will cut two relief holes into the cowl for hot air to escape.

capevettes,
I did check the accuracy of my gauge with an IR gun and it is spot-on.

 

Didnt have the IR gun around at home but the last time i checked it, before the air dam was installed, the gauge in the car was showing 20 degrees higher compared to the IR gun.

 

mvisible, if your showing 230 and your gauge was showing 20 degrees higher than the IR gun showed, I'd say you're in good shape. 210 is not too hot for these engines to be running.

 

Still check/verify/adjust your timing though...my '68 small block was overheating constantly, so I installed an aftermarket aluminum radiator, which kept me from pegging and occasionally boiling over, but the car still ran hot. I found out my timing was set at the book spec for the '68 A.I.R. setup, which is 4* BTDC, AND my vacuum advance was shot. I replaced the vac can and set the timing according to Lars' instructions and the sticky on this board; now I can get it up to 200 deg for a second or two if I drive it hard enough on a hot day, but it comes right back down to 170 - 200 deg (verified with the IR thermometer)...plus it runs noticeably better...

Cheers,

Chris

 

Pardon me - and with all due respect, but you say your dad has been a mechanic for years and years? Yet you guys tried running without a thermostat? I'm sorry but that does not work.

Start with the seals around the radiator. If that does not work, then I would try dual Spal fans. They seem to be the standard these days by which all electric fans are judged in C3 Corvettes.

I tried a single fan on mine and got not a bit more cooling than I had with the OEM fan & fan clutch configuration. Dual Spals fixed my stroker right up.

 

Doesn't it work if it is a sticky thermostat? If the thermostat stuck partially open then removing the thermostat would cool the engine and would indicate that it needed replacement. To say "that does not work" is just wrong in that case.

 

I owned a 79 Vette brand new it had AC and 4 spd and L82 and WAS BLACK ( worst color for staying cool) .....also glass tops ..and all the stock items ........ it ran around 200-210 most of the time...... maybe 215 at the beach w/ac on in traffic...... This seemed to be normal for these years cars. , but worried me after years for 180-195 temps in older vettes.

The 1979 L82 wAC and 4 spd HAD AN ADDITONAL FRONT AIR DAM EXTENSION rivited on to the plastic normal one. So, CHevy realized air flow using all the smog and hight temp heat for converters need for lots air to be channeled into the front of the car. 220 is really hot , when your used to seeing 185 . Everything in the engine compartmnet is red hot it seems

This EXTRA HEAVY rubber -like EXTENSION is OFTEN 99% odf time missing from what I see. My 74 454 w/AC has a simular additonial air dam rivited on to the plastic air dam. If you don't have a 79 factory assembly manuel , then you need one. You can study the pics and see all the little seals , and foam , check part numbers for CORRECT FAN and CLutch , you can see the special L82 lower air dam extension., put on what you are missing. CLean out the radiator , they get limed up . Flush out the fins on the outside of bugs and dirt. .

This item will make a diff. in slow around town driving . TEMPS are always below 195

 

UPDATE: I just installed mine too. Dropped the temps about 20 degrees. I also removed my control arm dust shields to increase air flow out of the engine compartment. Still have a bit of over heating to deal with at idle with no speed and at 70mph, but that air dam really helped. Will look at timing now.

 

Got the same results here


Moving on to the timing i did some research but i couldnt find what my proper timing for my engine would be. Its a TJC engine which im guessing is a truck engine. Does the same 46-52 degree timing apply for these engines?