Upper Radiator Hose Pressure??

-
S

SDHomesteade

Well-Known Member
Joined
Mar 31, 2014
Messages
128
Reaction score
3
Location
South Dakota
Hiya all,

Just got the wifes Dart all up and running again (Starter went out finally) and Noticed something peculiar. When the Car is Running, and even after it shuts off and sits for a while to Cold, the Upper Radiator hose is HARD. Like it's got a **** ton load of Pressure in it. Even after Sitting for 2 hours and cold again, I can pull the Cap off and it's under pressure. I replaced the Thermostat when I did all the tune up and new fuel pump and such (less than 100 miles on the new thermostat). It's the /6 in it and even after pulling off the cap, letting the pressure out, and then putting the cap back on, then starting it, not even 10 seconds after starting it the Upper radiator hose is Hard from pressure again. (Yes My Thermostat is installed Correctly). Anyone know what might be causing this???

Wife's Daily Driver so any help would be Greatly Appreciated, it's got me dumbfounded and the only thing I can think of is the Thermostat is bad. Looking for any other possibilities.

Dave
 
Is the overflow tube clogged? Also hows the rad cap look?

Headgasket a possibility
I believe a Compression and leakdown test are in order
 
Overflow Tube is Clear, Rad Cap is old.

Not showing any moisture on the dipstick or in the oil.

It's Just weird, all my other cars while running, I can squeeze the upper radiator hose and it will squeeze, but not this one, even right after starting. From the time it takes me to start the car, to walk to the front of the car and squeeze the hose, it's full of pressure. The Car Sat for almost 10 years before I got it. Changed the oil, filter, replace all the electronic stuff from Ignition control module to ballast resistor to battery cables and starter and wires and plugs and cap and rotor. Even got a new Fuel tank and Pump and carb rebuilt before starting it for the first time in 10 years. Once it was all replaced she fired right up and purrs like a kitten. Did not replace the Water pump however and when I got it, the Radiator was completely dry.
 
Somethings pressurizing the system, supposedly a bad head gasket can leak exhaust into the cooling system from what i read but its a thought
 
Just because the stat is new, doesn't mean it's good. Pull it and put it in a pan of water, use a candy thermometer to see when it is opening, IF it is opening.
 
Will do the simple thing first I guess and pull the Thermostat, I have plenty of replacement gaskets on hand so that is the cheapest option for me right now. Thanks for the input fella's.
 
Also, check the bottom hose to see if it is open, or that it isn't collapsing when running.
 
Pressure test the cap!
If it relieves at 15 or less, it's all good. The system pressure cannot exceed the relief valve. If the valve does not relieve, the pressure will find a way out.And it won't be pretty. Nor convenient!

FWIW; I run 7psi caps in all of my older cars, with mechanical fans. The hoses last forever, and the rads never develop leaks.
 
Yeah, she came home from lunch so didn't have enough time to mess with the Thermostat. THe Rad Cap is pretty old. But I did Start it today while she was home for lunch with the Cap off. The Fluid was just above the top of the neck, and as it was running, the level went higher and higher (still reading cold on the temp gauge and hose was not hot) and then overflowed gradually. UGH. I don't have time for this **** LOL, too much other stuff to do LOL.
 
I would also recommend a couple of things. Number one is to use the pressure cap that the factory recommended with a cooling system in good condition. For most Chrysler products from the era ran a 16 psi cap. Like said elsewhere don't assume that new means good. Lots of defective stuff out there so test it your self before you trust it.The higher the pressure, the higher the boiling point. The reason that cars overheat with no thermostat and a bad cap. Use a high flow thermostat that has a large bypass hole in it. This will prevent a stuck thermostat from harming your engine from an overheat condition.
 
It's not overheating though. The Gauge is just barely reading over the L Mark on it. Running a 160 degree thermostat in it. It's just building up an abnormal amount of pressure I think, that I can feel in the hose. My Other /6 in the Aspen isn't running right now to compare it with but on My Mini Van and Ford Pickup, I can squeeze the upper rad hoses fairly easy.
 
I'll pick up a new cap for it (and the aspen) while I am in town on Saturday (nearest parts store is 70 miles away).
 
I have to agree with a lot of the posts above, and especially with AJ.

It's not a bad thermostat if it runs the temps you say it does.

A head gasket leak can cause tight hoses, and the absolute simplest way to diagnose that is with a cooling system pressure tester.
It goes on in place of your radiator cap and has a pump for building initial pressure and a gauge for watching the pressure.
The gauge on the tester will climb to a certain point and is supposed to level off at some point before it gets to hose popping pressure.
If it has a head gasket leak the pressure will steadily climb until it either blows a hose or pops the radiator or blows past the tester cap.
It really should be done by someone who knows what they are seeing on the gauge because an increase in pressure is normal, but only up to a certain point and NO more.
With a bad head gasket the pressure will spike every time the engine is revved until something gives. (hopefully the cap relief)

The fact that it hasn't exploded a hose and doesn't overheat means it is probably not a head gasket (think what 120- 140 lbs in the radiator would do)
Usually it blows coolant past the cap, aerates the coolant and THEN overheats if it's a head gasket.

Also note that in an open system (a system without a recovery type tank) the coolant is supposed to be a little below the cap opening to allow for expansion.
A closed system pushes any expanding coolant into the recovery tank and then pulls it back into the radiator when it cools down keeping the fluid always at the very top of the radiator opening. (if it's working right)

A puke tank and recovery tank are different animals.

I said I have to agree with AJ because if it's not overheating the it's probably not a head gasket leak, but just needs a lighter pressure cap to allow a little more expansion without so much pressure that it might be hard on the hoses, radiator, heater core and so on.

An actual recovery system (if it doesn't have one) would just make it that much more reliable and maintenance free as far as coolant level goes.
 
Thanks for the input, I'll be picking up the pressure cap as well when in town on Saturday.

It's got the recovery tank setup on it. Overflow tank is what I call it though. Little Plastic Tank next to the Radiator with the hose from the Radiator to the plastic Tank. Tube is Clear but nothing is going into it when the fluid level does rise in the Radiator. Didn't have time to pull the plastic Tank before she left to go back to work. Will do that when she gets home tonight.

Thanks again for all the suggestions and help.
 
I've also got new hoses coming from Rock auto that should be here tomorrow. Figured I would replace them too while at it, just wasn't thinking about the Cap when I ordered the dang things.
 
Find someone, maybe a rad shop who can run a chemical test for head gasket. This is a chemical that tests for combustion gases, otherwise known as a block (blok) test

http://www.blockchek.com/instructions.htm

hand.gif


2011-03-07_025510_block_test.jpg
 
The Lower Hose is NOT collapsing. She got home and the Hose was really really hard from the pressure built up in it, NOTHING coming out of the Overflow Hose into the overflow tank or even disconnecting the hose nothing came out. Gotta let it Cool off for about 2 hours before I even wanna attempt to pop that cap.

Safe to assume it would be the Cap then??

Also, has anyone bought this one or used this Pressure Tester from harbor Freight?? It doesn't specifically list any of the OLDER cars in the downloaded PDF Manual online.

http://www.harborfreight.com/radiator-pressure-tester-kit-69258.html
 
67Dart273 said:
Find someone, maybe a rad shop who can run a chemical test for head gasket. This is a chemical that tests for combustion gases, otherwise known as a block (blok) test
Click to expand...

Thanks for the info and Link, Live out in the middle of nowhere so nearest Rad should would be 70 miles away, I don't trust it to make it that far. Might have to get this Kit and do it myself if the smaller fixes don't work.
 
SDHomesteade said:
The Lower Hose is NOT collapsing. She got home and the Hose was really really hard from the pressure built up in it, NOTHING coming out of the Overflow Hose into the overflow tank or even disconnecting the hose nothing came out. Gotta let it Cool off for about 2 hours before I even wanna attempt to pop that cap.

Safe to assume it would be the Cap then??

Also, has anyone bought this one or used this Pressure Tester from harbor Freight?? It doesn't specifically list any of the OLDER cars in the downloaded PDF Manual online.

http://www.harborfreight.com/radiator-pressure-tester-kit-69258.html
Click to expand...

Actually I'd be surprised if that set even held air:D

Bottom line is if it doesn't overheat, or you don't have to add coolant every day or doesn't have coolant or oil in places it shouldn't you don't have a head gasket leak.

I'd try the lighter poundage cap and see what it does. (bet it's fine)
The hoses will just be that many pounds less tight. :D

The deal with the tank is if it just catches pushed out coolant then it's not a recovery setup.
Most any new cap will be a recovery type cap, so as long as the little hose from the radiator is submersed in coolant in the tank it should start working as a recovery unit.

If it isn't already.
 
Well, my Recovery Tank or whatever it is, is quite Long, has place for a rubber hose connection on it to a tube that goes into the bottom of the tank and then another tube on the other side of the tank that goes from the top of the tank to the bottom and is open on the bottom (overflow) and holds about 3 qts of coolant if I guess right. It's a got a 1 qt and 2 qt line on it.

I'll be in Newell Tomorrow and I think they have a small auto selection there at their hardware store that might have a Radiator Cap. If So I will pick up one or two there. Otherwise, will have to wait till Saturday.

The Harbor Freight Pressure tester has some pretty fairly Decent Reviews and I have bought lots of things from there that are still going strong.
 
SDHomesteade said:
Thanks for the input, I'll be picking up the pressure cap as well when in town on Saturday.

It's got the recovery tank setup on it. Overflow tank is what I call it though. Little Plastic Tank next to the Radiator with the hose from the Radiator to the plastic Tank. Tube is Clear but nothing is going into it when the fluid level does rise in the Radiator. Didn't have time to pull the plastic Tank before she left to go back to work. Will do that when she gets home tonight.

Thanks again for all the suggestions and help.
Click to expand...

There's your answer right there;either the pressure is normal or the cap's relief valve is stuck, or the overflow hose is plugged.
 
Can't be the hose, I blew it (No Jokes please) and air came out the other end.

Thanks everyone for all the Suggestions and help. Will let you know how it comes out when I get the new Cap and hoses put on.
 
THANK YOU TO EVERYONE THAT HELPED.

Culprit was the Radiator Cap. Got one today, 16 psi is all they had, they don't even show a 7psi one listed. Put it on today after getting home from picking up the 86 Diplomat, put it on, Warmed it up while I disconnected the Tow Dolly, then drove it 10 miles and No pressure in that hose built up. Still going to replace the upper and lower hoses though, they feel kind of soft when the pressure isn't built up in there LOL.

THANKS AGAIN FELLA's
 
You must log in or register to reply here.
-

Back
Top