What causes back pressure on a 94 7.3 F-250 turbo 127k on it I just put a new radiator in because it was about to blow the neck off I drove it around for a while after I put the radiator in an it had water around the neck I'm assuming that it came up through the over flow I'm not sure this trucks been one problem after another since I bought it My uncle said it was a head gasket HELP!!!!!!!!!!
Back Pressure on Radiator
- Thread starter BlueCrew
- Start date
cm1hedge
Full Access Member
check for cumbustion gasses in the cooling system.
david85
Full Access Member
I think your uncle is right......sorry.
That much pressure can only come from combustion pressure getting into the cooling system. You want to deal with that sooner rather then later. Diesels that leak compression gasses can actually erode the block and head mating surfaces around the gasket breach.
Only other thing might be the rad cap not opening, but thats a long shot.
You finding any foam in the coolant when it overflows?
That much pressure can only come from combustion pressure getting into the cooling system. You want to deal with that sooner rather then later. Diesels that leak compression gasses can actually erode the block and head mating surfaces around the gasket breach.
Only other thing might be the rad cap not opening, but thats a long shot.
You finding any foam in the coolant when it overflows?
Diezel_Cowboy
It's not like a real ***!
Start with the simple stuff first. What pressure cap are you using on the radiator? How old is the cap? The radiator develops pressure as it heats up so a little bit of coolant at the neck could be coming from a cap that isnt sealing well or from the expansion tank tube not sealing well. You have said nothing that would indicate a blown head gasket.
OK, I'm trying to analyze this statement. Let me see the logic here. We've got a perception that the fill neck, where the cap is, is going to blow off. Why? Is the neck to tank joint leaking? Is the radiator cap leaking? Is the coolant recovery bottle overflowing? It seems to me you have one of two things going on. Either something is in your radiator that wants to get out so badly, it won't fit through the presure relief in the cap, OR the radiator CAP is bad. Why do we replace a radiator, if we have a failing cap? I would assume that since radiators don't usually come with a cap, that your using the same cap as before, and having the same problem as before. Tell me why I shouldn't be thinking.... Duh? I'm going to assume that it's because I'm not reading something I should be here. Have you tried running the engine up to temperature without a cap on? You shouldn't be seeing bubbles in your coolant.
I didn't get much of a chance to work on the truck today. I did see that the cap said it was 16 pounds an it has been on the truck since I owned it. It was leaking at the bottom of the neck, cracked all the way around. I'm gonna buy a new cap in the morning I'll see what happens then
icanfixall
Official GMM hand model
That cap is the wrong pressure. Most here will only run a 12 lb cap but some, like myself have had real good luck with a 7 lb cap too. The perssure only makes the boiling point of the coolant or water that much higher. These cooling systems will so the alarm at 242 degrees. No need to run it hotter than that even if we could.
I went to AutoZone this morning an the guy looked up a cap for my truck, 13pounds. I ran the truck up to normal temp like Mel said with out the cap on first. Didn't see any bubbles I let it cool a bit then put the new cap on it. Ran it an watched for a leak, none that I could see. So I'm hoping thats all it was. How many of you guys have wider tires on your truck for better traction. My truck is used around the farm, an its getting stuck a little more than I'd like
