Al.P.

Gentlemen,

I have a issue with a 2004 C5 Corvette convertable 5.7L. I purchased the car about three years ago. 150k miles on it at this time. After the first year I had to replace the radiator. There was a crack on the left side tank on the top above the hose. A year later it cracks identicle, i replaced it again, im on the third radiator. After replacing in the spring of this year here again I have sprung another crack in the same exact spot, less than a year later. This is my third radiator since I have owned the car. Any ideas as to why this is happening. The only thing I can think of is the pressure relief in the surge tank cap is bad and no allowing pressure to escape over 15psi. Any other ideas?

tbrowne

Is it possible the radiator hose is too short putting pressure on the side tank? Radiators do go from time to time but there is definitely something wrong to have that many with the same problem. Motor mounts could be a source. A bad mount could conceivably let the engine move enough to pull on the radiator hose enough to crack the plastic over time. Just some initial thoughts.

Robrote

I agree with tbrowne, there has to be a stressor someplace on that radiator. Not to spend your money for you, but at this point, buy a Dewitts radiator and forget about it.

Al.P.

Yeah thats what i been looking at. But holy crap thy are expensive. jeeze.

SilverC54me

What kind of hose clamp is being used, the factory one or the typical hardware store screw to tighten clamp?
The screw kind can be tightened more than the factory one causing the neck to crack.

Gary

Al.P.

When I replaced the first one I used a stainless screw type. However the crack starts at where the plastic end tank meets the alumimum radiator core and moved outward towards the neck but not originating at the neck and not in the neck itself.

Velocity_Vette

Did you ensure the rubber pads were present both on the lower radiator support and under the top radiator shroud when replacing the radiator? If they are missing anywhere or damaged, they would allow the radiator to physically contact secured portions of the vehicle which it is not supposed to do (it's effectively suspended in air cushioned by the pads). That jostling and contact of the radiator could stress the plastic side tanks, causing cracks.

Al.P.

yes they are there but i will check when i pull it to replace.

Aquarian

WOW!!! mine went out yesterday , started smelling antifreeze and then temp gauge started to climb. pulled over had liquid on drivers side of rad and called for a tow home. Was just looking at the Dewitts...I know they have an excellent product so I have to bite the bullet. Only want to do this once.

pjensen

My original radiator lasted 11 years (130,000 miles). Replaced it with a GM OEM radiator which lasted 3 years before it started leaking (on the plastic side piece). It has a lifetime warranty so I can pull it and get a new one.

But I really don't want to do this again. Ended up buying an all metal radiator from speedcooling.com for $315. Unfortunately they sent the wrong radiator - I have an automatic (2004) which has quick disconnects. Still waiting on the correct parts to be sent. But the radiator looks great.....

That might be an cheaper option.

Al.P.

Well i think I found the culprit. Yesturday I took my Pressure Cap to Advanced auto and thru it on the tester. I pumped it up at 18PSI it kept going up. Somewhere above 25PSI I heard a pop and the pressure went down to 18PSI. I pumped it up more but it maintained 18PSI. I removed it from the tester and perforemed the test again. It continued to maintain 18PSI. Look like somehting made the valve stick hence the pop over 25PSI. I bought a new cap and will change the radiator next week. Hopefully this is it.