As several folks have mentioned the C5 is a bottom breather - butw hat does that mean?

1) The center section of the front air dam directs air up to the a/c condenser and radiator. If its missing then no air is being directed up. If its not there on your car, then reproduction units available from forum vendors. If it is there, try pushing against it to make sure it not folding back too easy. It is designed to fold back against sprint tension encase you encounter an obstacle and then swing back into position.

2) A/c condenser and radiator get clogged with crap that is sucked up off the road. You can do a quick visual inspection, but that's only good if say you have a bunch of leaves or a plastic grocery bag up there. Take the time to remove the upper radiator core support (its just four (4) 10mm bolts). That way you can look down between the a/c condenser and the radiator. Do NOT be surprised by the shear amount of crap that may have accumulated in there. You can try to blow the debris back though the cooler, but a garden hose with a long attachment that is angled at the end works much better. There are screen guards for the opening that you can buy and install to keep most of the larger debris from getting sucked up and trapped up in there.

3) Its critical that the foam seal strips are still there on both sides of the a/c condenser and the plastic shroud. If they are missing, then all the high pressure air flow just spills out and does not go through the coolers. If the foam strips are missing or have disintegrated, then you need to buy something similar to this and replace them;

https://cleverbrand.com/products/1-w...31685661163572

I used the 1" x 1" closed cell neoprene foam with adhesive on one surface and stuck it to the plastic shroud. One roll is more than enough.

 

I found your link on the foam strips, but no other hits on original parts or diagrams. You have any pics or diagrams ?

 

This post shows the foam stripes in question. The factory applied them to the outside edges of the a/c condenser. You would just need to clean the surface with brake clean before applying the new foam stripes.

https://www.corvetteforum.com/forums...post1598507662

 

The center air dam doesnt just direct air. It also causes a fairly strong vacuum to form behind the radiator, and cool air then rushes thru the radiator.......

 

Thermostat was changed around 2 years ago. Before the water pump was replaced by the mechanic, it was hovering around 215-220. From the time I got the car, I never had it run anywhere around 200 degrees. I bought the car back in 2017.

Once the water pump was replaced I started noticing the temps were hitting well above 230. So when I checked, it was a busted coolant reservoir tank leaking from the sides and the nipple area which was cracked as well.

That got replaced but the problem still persisted. Which is where we went to buying a new radiator for it. Old one had a dent on the bottom since the bumps and dips in my local area are nearly everywhere. New radiator didn't solve that issue.

Air dam is one thing I didn't check, but from what I checked underneath, there was a plastic rectangle piece that was twisted right around the air dam area that was dragging on the floor. It was removed by the mechanic, but it didn't look like the air dam pieces.

I will have to double check tomorrow and see.

Good to know! That is not something I checked as far as the seals and air dam.

 

So, if I understand you correctly, the engine was 10°-15° hotter than normal to begin with?

It’s really seems like air flow obstruction, major air pocket in the engine, or bad thermostat. I would seek out a mechanic who has a vacuum coolant filler. This method virtually guarantees no air pockets, and the water pump can’t pump air! 👍

Also make 100% certain that AC condenser is clean.

 

From what I can remember yes. But I never bother to look underneath if the air damn was broken or twisted.

But as of right now, I looked yesterday and there was no front air dam. Side pieces are there still, but front piece is completely gone. No clue if the mechanic tossed it because it was broken or it got removed some other way.

Luckily a guy local to me was selling a new front air dam that he had lying around from GM. Will have that installed and hope it will solve the issue.

 

It will solve the issue, no doubt in my mind.

 

Fingers crossed! It’s definitely going to help.

 

So update on this. Had this installed Saturday and holy cow! It was the issue, cooling holding steady at 205-210 now. Can't believe one piece was the causing the issue.

Only thing now to solve is the low coolant sensor messing up.

But I thank everyone for the help here! If I could buy a round of beers, I would.