combustion in the coolant?
 

I have gone through 2, TWO! cold case radiators in my Blazer. I have to give props to coldcase though, they sent one to replace the first one I purchase free of charge last october and that one started leaking today. I walked out to the driveway and it was leaking, hadnt even started it yet.
needless to say i am a bit pissed, called coldcase and they said take a pic of the serial number and the leak and they will send out another!! many props to them and their lifetime warranty.
Now, the dude on the other end of the line told me that there could be "combustion" in the coolant? and that could be causing the pressure that is blowing the radiators apart. I personally, in all my years of being a home garage gearhead have never heard of that until today. He said that there wouldnt be the usual signs of water on the plugs or coming out the tailpipe but could be causing the pressure, said he had a 454 that was doing this. Said he changed the head gaskets and the problem went away.
Can a head gasket be bad as to let combustion into the radiator and not into the cylinder ?

Re: combustion in the coolant?
 

The radiator cap should pop before the radiator fails.
If you have a bad head gasket it can pressurize the radiator, leak externally or both.
Normally you should see a loss of coolant either way.

Re: combustion in the coolant?
 

2nd on the cap releasing pressure before the radiator splits. Get a new cap even if current one is fairly new. QC could have failed.

Could be possible that you have a small enough head gasket leak or crack to let combustion air into the water spaces but not water back into the cylinder. Once the fire lights, pressures get really high, hundreds if not into the low thousands of PSI. The max for the water should be the cap rating. Test run it with full water but cap off. If there is leakage, you should see bubbles in the radiator.

Are the radiators leaking from the same spot? Maybe some assembly person needs a bit of additional training.

Nice to hear that a company stands behind their products.

Re: combustion in the coolant?
 

Sounds lie the tech was referring to combustion gasses leaking into the coolant.

All agree this should force the radiator cap to reach max pressure and vent out excess.

If the radiator is swelling before the cap releases, there must be something wrong with the radiator design or build.

Are you mounting the radiator solid to the chassis? If so, perhaps the frame is flexing placing extra stress on the radiator.

Here is a simple radiator test kit to check for combustion gas in the coolant.

https://www.amazon.com/Block-Tester-...YaAuw0EALw_wcB

:chevy::chevy::chevy:

Re: combustion in the coolant?
 

we use that same block test kit at work and it's simple and accurate.

Re: combustion in the coolant?
 

I agree totally but, don't you think that even if the cap was bad that it would be forced open before blowing out the radiator?

Re: combustion in the coolant?
 

I agree as well, the cap should relieve the pressure even if there are gasses in the coolant even if the cap is bad, with enough pressure to blow out the radiator you would think that that amount of pressure would override a bad spring?

Here is my radiator... https://www.coldcaseradiators.com/pr...?sku=GMT558ALS

The radiator sets on rubber on the bottom and the clamps at the top also have rubber in them.
This is in a 1972 K5 Blazer with a 2000 LS1 swap.

Thanks for the test tool link

What cap would you suggest for this radiator and set up? this is my first LS so im in the dark as what to get.

Re: combustion in the coolant?
 

I prefer the Stant brand 16 lb cap.

Re: combustion in the coolant?
 

ok.
So, now, worst case scenario, lets say I have to yank the heads and do new gaskets, what is the best gasket rebuild kit out there for a turbo im going to put on it next year? obviously i will have to have them milled to clean them up if this is the case

Re: combustion in the coolant?
 

When I do LS swap into whatever I like to mount the radiator with the rubber u-saddles top and bottom not "L" brackets welded on the side tanks. Pic of my 68 using a generic LS Afco dual pass radiator.
Having said that on my LS6 swapped 98 Wrangler the radiator is a side mount but has a rubber insulator between the mount and the tanks. No issues for 15 years.
See pic.

Re: combustion in the coolant?
 

Thanks Short, I have the same set up in my 72 blazer that you do in your 68 and the cold case fits perfectly.

Re: combustion in the coolant?
 

One more thing, could not "burping" the system correctly cause all this pressure?

Re: combustion in the coolant?
 

I also had my first Cold Case radiator leak after 6 months on my LS swap. It was leaking where the fins attach to the right side tank. I have mine set up with traditional coolant and an overflow tank. Coolant level in the overflow goes up/down as it should, so I'm pretty confident my cap is working fine. As with your situation, Cold Case sent me a no hassle replacement radiator. I feel like this may be more of a manufacture defect than combustion pressure in the cooling system.

https://live.staticflickr.com/65535/...59e4183b_b.jpg

Re: combustion in the coolant?
 

Their radiators are junk. I went through 2 of them on my truck in 2 years. My brother has gone through 4 in 5 years. They all start to leak where the tubes go into the header, exactly like hewittca is showing above. I bought a custom radiator for my truck and have had no issues at all.

They do not even ask you to return the old radiator anymore. Get rid of the ColdCase and buy a quality radiator. Problem solved.

Re: combustion in the coolant?
 

Well that sux, where did you get your radiator? I really don't want to blow my engine because of a $#itty radiator. Here is what mine look's like

Attachment 2361615

Re: combustion in the coolant?
 

I have had a Champion radiator in the 68 for 6 years and never had an issue.
It wasn't expensive, fits perfect and works well.
I did add a zinc plug instead of a petcock to help with any potential electrolysis issues.

Re: combustion in the coolant?
 

I've used Griffin, Afco, and Be Cool radiators. Never an issue. The one in my Jeep I bought from Novak out of Logan UT. The make/supply Jeep swap parts. I believe they get them from Griffin. They buy the bare radiator and then they fab the side mounts.
My latest project is a 80 Camaro with a LS swap. I'm using a generic LS Be Cool radiator. Biggest I could fit.

Re: combustion in the coolant?
 

Yes, that looks like it is coming from there the tubes go into the header panel. I got mine warranteed and and sold it brand new for $200.

Mine is Power Cool Manufacturing radiator. I was shocked how heavy it was for an aluminum radiator. Mine is an L83 so I wanted the inlet/outlet and the drivers side for a dual pass instead of the LS style on passenger side.

Re: combustion in the coolant?
 

yeah it is a gusher, I had it under pressure to get hte pic for the warranty.
Great idea on selling it when it gets here :metal:

Re: combustion in the coolant?
 

Thanks! ride is lookin good!