help rad cap go boom

[88beast]

ok well the truck is overheating so i pulled the original 600k rad thinking thats problly the issue and it looks good a little crummy inside but not real issues but the fins on about 1/3 of the rad right in the air flow are smashed and icant see how
also its got a tstat from advanced in it (i know wrong one thats why i mentioned)

but what it does is ill be driving for a bit (not too long) but itll just blow coolant out from under the seal for the cap ***? any insight would be nice

 

[87crewdually]

Did you replace the cap with a 13lb? May just be a faulty cap.

 

[LCAM-01XA]

Replace the cap and also the hose between the radiator and the overflow tank - once the coolant goes past the cap valve it should go into the overflow tank, the fact that it leaks past the cap seals instead suggests to me that either the cap seal is bad or the hose is plugged or both.

 

[88beast]

cap blew replaced cap new 13 psi cap blew in a week old cap was also 13 psi
hose to tank is fine its got a downward slope is fairly new and in good shape the old tank was cracked when i got it so i replaced hose then and the tank fills and emptys pretty easy as it should

 

[LCAM-01XA]

Then maybe you have a compression leak from a cylinder into the cooling system due to a failed head gasket?

 

[88beast]

no bubbles so far and the exhaust hasnt changed no water in oil or vice versa ill heat it up when the rad is back in and look for bubbles again tomorrow
i was considering the fan clutch cause its free but moves with resistance when hot or cold but its been like that since i got it

 

[Brimmstone]

Had the same issue with my flatbed and couldn't find where the issue was. I tried several radiator caps and rigged up my cooling system tester so I could drive it and see the pressure as I drove. The pressure got up to 14 1/2 pounds but never went higher than that. Did combustion tests and found nothing. Finally got ticked and stuck a 16 pound cap on it. Truck runs cooler now and no longer blows antifreeze out of the radiator. To the people who are going to say that it will blow the radiator or the heater core with the increase in pressure. I check with several radiator shops in town and was told by all of them that the 3 pound difference wouldn't cause any problems. Three months later still no issues and I don't expect to ever see any.

 

[88beast]

something else i noticed is higher egts about 200 degrees higher but its a new pyro so idk if thats just it breaking in or what still yesterday and today i pulled and cleaned the rad and hoses replaced heater hoses and the tstat
tstat had the gasket that comes with it and the paper one on it
i used just the paper one
topped of with water for now
soon im going to put in a coolant filter and hook up the mech temp gauge and all new coolant for the 5th time in 2 years

 

[88beast]

so heres my supplies list for all the work
rad flush (didnt even use yet)
40 gloves
water
well loved coolant
2 qts tranny fluid when i leaked so little you didnt notice it on the stick
2 condoms (note to self atf eats condoms) my buddy had um redily accessible idk y but hey it stopped the drip for a min
2 days and about 10 extra hose clamps and some 5/8 heater hose

 

[DeepRoots]

so what is the actual water temp you are running?
what is the actual coolant pressure?

without knowing these, replacing parts isn't going to yield the results you want (unless ya just get lucky)

 

[88beast]

im going to finish hookinig up the new gauge i started it and in the middle my buddy needed towed he broke down on the way to meet me so it got put aside
how ya measuer pressuer ? cause i dont have the sxpensive adaptor cap kit

 

[RLDSL]

im going to finish hookinig up the new gauge i started it and in the middle my buddy needed towed he broke down on the way to meet me so it got put aside
how ya measuer pressuer ? cause i dont have the sxpensive adaptor cap kit

You can get some pipe thread nipple adapters to go into the heater line and tap in any pressure gauge, a cheap oil pressure gauge will work and run the hose into the cab When you are done testing pop a pipe plug in the fitting you used for the gauge. Done this many times works great.

 

[88beast]

ok let me get this straight cause what makes sense and what i get out of taht are different
so youre saying
t the heater hose
npt plug in it with the oil pressure adaptor then run that into the cab correct?

 

[RLDSL]

ok let me get this straight cause what makes sense and what i get out of taht are different
so youre saying
t the heater hose
npt plug in it with the oil pressure adaptor then run that into the cab correct?

Sounds about right. You can get a T fitting that has large enough outlets to thread a 5/8" nipple in each end and if you can't find one that has a 1/8" npt on the middle outlet you can adapt it down with pipe thread bushings , thread the oil pressure gauge line into that ( some gauges come with a selection of bushings for the larger holes) Then run teh hose through one of the holes in the firewall, that thin spaghetti line is easy to poke through and then set the gauge on teh floor or tape it on the dash temporarily so you can see it better They usually give you about 10ft of that line so it should reach . That setup is sturdy enough to drive around for a few days , it will be plrenty safe, just keep the line off anything too hot, slip it into some of that wire split loom if you need to to keep it off things.
I;ve had some that gave me nightmares until hooking that setup on to geta good picture of how the pressure was behaving Sometimes you wont get any leak from a head gasket until under heavy load then all the sudden the gauge pegs on and off as the cap releases pressure

 

[DeepRoots]

thanks RDSL,
88 THATS why you wanna be able to see the pressure in the cab.
idling staring at it with an open rad cap might not show ya anything.
Watching it is in the cab while you're rolling is different.

On another note, a coolant temp gauge is like $15. Or better yet get one of those 3 gauge deals at autozone.
There is NO excuse on these trucks not to have at the min an oil pressure and coolant temp gauge.