Autotechnica

Hey guys, I'm having a consistent problem where my upper coolant/rad hose keeps blowing off from the radiator side. I actually have a BEHR radiator which I replaced a couple years ago. I also recently replaced the hose thinking maybe it was defective. Today, the same thing happened. I give it maybe half throttle and the hose blew off spewing coolant everywhere. The hose seems to "click" into the metal clamp on the radiator properly once I push it in. I've even tried removing the clamp completely and reinstalling it after the hose has been pushed in, same outcome. After it clicks in and pull it as hard as I can it doesn't come back out. It seems very tight. It must be under very high pressure. I'm lost as to what it could be. Too much heat/pressure in the cooling system? I always bleed the system properly after ever drain and refill.


I have moderate mods, 178mm ASP crank pulley, eurocharged tune, EC heat exchanger, intake, exhaust, etc.


Is this happening to anyone else? I can't imagine a 178mm (~18psi) boost is too much for the car to handle. I'm running around 90-95C engine/coolant temp while doing some spirited driving.


Thanks,


Bry

Speedriven1

Make sure the clip is positioned correctly. The coolant system should be under a consistent coolant pressure.

Supgee

Yeah, do what speedriven said. I think your little spring clip is not positioned properly, or perhaps the spring clip has become weak and no longer providing enough force to keep the coolant hose in place, and you need to replace that too. (not likely)
The cooling system is under consistent pressure, around 14-16psi.... its not like when you rev the engine the cooling system pressure spikes very high...

Autotechnica

Hmmm, thanks guys. I'll check the spring clip but it looks like it will only clamp on one way. There's a track then this little stopper that the clip clicks into. Difficult to explain. BTW, when I insert the upper rad hose into the rad should I just push the hose in while the spring clip is already in position, or do I need to remove the spring clip, push the hose in then re-clamp? Ughh, why couldn't it just be a regular rad nose that uses worm gear clamps.


I was thinking that maybe the spring clip was weak. I was prepared to wrap rubber around this spring clip then tighten a worm gear clamp over it ensuring the spring clip won't have any chance to move or become lose. First thing I'll do it snap a pic of the top and bottom of the clip while installed and you guys can tell me if it's correct or not.


BTW, thanks for all the help. I was under the impression that while my crank pulley spun faster, the water pump would increase coolant pressure.


thanks,


Bry

Autotechnica

Reviving this thread because i'm still having the same problem. Only this time, I have a brand new BEHR radiator and a brand new upper coolant hose. what is going on? The hose half blew off this time and coolant started dripping. I just pushed the hose hard and it "clicked" back in. This is pretty much exactly what happened to me last time on my previous BEHR rad. I recently had a leak at the seams with my less than 2 year old BEHR rad and replaced it. I'm having some terrible luck with these components.

So this has nothing to do with maybe a Johnson I/C pump and a 178mm crank pulley spinning the water pump faster? I'm all out of ideas. Should I just revert back to the stock crank pulley? Is the torque from the engine pulling on the rad? Why am I the only one having this issue? The radiator and hose was installed by mercedes. They had no idea what's wrong. If anyone has any suggestions I would greatly appreciate it.

thanks

husqvarna

Replace your expansion tank cap

Autotechnica

I replaced the cap last summer. Would a cap even cause this issue? Does excess coolant vent from the cap or something? I'm starting to think my previous BEHR radiator had leaks from the seams because of too much pressure. However, I thought there was some sort of bleed valve on the rad if there was too much pressure or coolant?

thanks.

Shadow5501

Blowing off radiator hoses is a classic symptom of a blown head gasket. When you give the engine significant throttle, the cylinder pressurizes the cooling system and blows the hose off the radiator. I'd start with a check for the presence of exhaust gasses in the cooling system and go from there.

Autotechnica

I may have to get that further diagnosed. However, I don't have the classic signs of a blown head gasket. No air bubbles in the coolant, no milky white foam on my dip stick, no coolant loss or other coolant leaks, no white exhaust smoke at idle.

BTW, I noticed that the little metal clip/spring that holds the upper rad hose in place was just slightly out of position (about 3mm). I could tug on the hose and see that there was play where the hose seals. I pryed the spring clip counter-clockwise and it locked the hose in place, no more play. I'm not a huge fan of this spring/clip design. I don't understand what was wrong with a ring clamp and a hose. Anyways, could enough pressure build up to push the spring clip and make it turn allowing the hose to slip out? A regular worm gear clamp on a regular hose neck would probably snap the radiator hose neck long before the spring clamp would let go. Terrible Mercedes design IMO.

Also, do any head gasket sealing products you can add to the coolant work? I'm really hoping it's not the head gasket. I've heard of kits you can buy to test for exhaust gas in the coolant. Should I take it to a professional to get it diagnosed? I always thought our cars had valves that bleed excess pressure or the overflow cap would release pressure or even blow off.

thanks!

Bryan

layzie12g

Does the hose blow off while your making a pull or just under normal driving?

husqvarna

If you can't diagnose the blown head gasket, just replace the tank cap.
The relief valve is in the cap. After that check how hard (inflate) is your coolant hose when you are at operating temperature.
You can check how ward is the hose of some other car to make a comparison.

If you don't smell exhaust gasses in the expansion tank, probably your cap is bad