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truck overheating


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magnum22
New User
randallconley35@yahoo.com

Jul 23, 2008, 7:26 PM

Post #1 of 18 (3825 views)
post icon truck overheating Sign In

i have a 1991 dodge dakota with a 318 that overheats when you drive. has new radiator, thermostat, and water pump. water not circulating good with cap off, and has bubbles. thought of air in the system, but don't know how to get it out. found one corroded hose from top of water pump to the motor, and replaced it. no leaks anywhere =thanks[code]


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Jul 23, 2008, 7:40 PM

Post #2 of 18 (3823 views)
Re: truck overheating Sign In

If it continues to make visable bubbles at radiator it might be putting combustion gasses into cooling system thru failed head gasketUnsure

I don't know of 318s to be "head gasket" eaters like some engines but it's possible. Try feeling upper hose by hand, rad cap on, cold with no pressure felt, start engine and if it pressures up quickly there's a suspect problem with gasses pressuring it up before the normal expansion of heat....

Check, check and double check before blaming a head gasket but I think it's in the cards,

T



magnum22
New User

Jul 24, 2008, 6:43 PM

Post #3 of 18 (3808 views)
post icon Re: truck overheating Sign In

omg!!!!
It would be so much better if the previous owner had put the wrong radiator in or something.
do you think the motor would have too much behind for itself after a new head gasket or possibly having the heads taken to the machinist? motor has 17900 miles !!!! omg omg omgPirate


magnum22
New User

Jul 24, 2008, 6:47 PM

Post #4 of 18 (3807 views)
Re: truck overheating Sign In

also, the radiator had some stop-leak in it


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Jul 25, 2008, 2:11 AM

Post #5 of 18 (3804 views)
Re: truck overheating Sign In

Stop leak could be the problem if too much was used in a feeble attempt to seal a head gasket which is near impossible with a sealer.

The gaskets - head, intake can leak any which way they seal. They don't all blow coolant out the tailpipe or in the engine oil.

It's kind of likely with what I see so far but certainly diagnose it right first. Pressure test cooling system it may show up with that or just leave pressure tester on system when already warmed up with cap off, put tester on and see if it continues to make pressure which it shouldn't and don't allow it to exceed system pressure of about 16# with a tester on it as it won't let go by itself at prescibed pressure.

At the miles if this gets down to needing the head gasket job I'd send the heads out of course and consider the overall state of the vehicle and your wants for more trouble free miles and do the timing chain if original.

These 318 engines have been historically very tough but at the miles the care along the way counts. If this is sludgy under valve covers, engine ticks, oil pressure slow to build up or runs lower norms at idle you should consider how much you want to invest in a sinking ship! Assess the overall engine condition is what I'm suggesting.

You can fix broken but not reverse neglect so easy.

Your comments about prior owner, stop leak and the work already done suggests the problem was known some time ago. How long have you owned it and what history do you have?

T



Guest
Anonymous Poster

Jul 26, 2008, 11:04 AM

Post #6 of 18 (3791 views)
Re: truck overheating Sign In

ok, so I'm the lady who told her man I thought the truck was o.k. -- we just didn't drive it far enough for it to overheat...
since our last post we looked under the hood of another same model truck and the radiator is the same as hers, but it's a v-6
we flushed the radiator in an attempt to un-clog any ports, then put a block sealer in with the same results, then replaced the bottom radiator hose because it looks like it was old enough to collapse.

motor still sounds good, oil pressure is good; the body and frame look good

don't have a pressure-tester- lead man at work made one one time out of a bicycle tube, but I forget now how he did that, plus we would have to remove the radiator to test it that way anyway,and I'm afraid that without a guage, I would over pressurize the radiator and cause it to leak

do parts houses rent pressure testers?

P.S. The seller sold us his problem,as much as I hate to admit it

I can't let this truck beat me. That's what's going on now.


Double J
Veteran / Moderator
Double J profile image

Jul 26, 2008, 11:11 AM

Post #7 of 18 (3782 views)
Re: truck overheating Sign In

Autozone does rent pressure testers...
Figure on about $85.00 with tax.



Jim


ms grease monkey
Novice

Jul 26, 2008, 11:12 AM

Post #8 of 18 (3782 views)
Re: truck overheating Sign In


In Reply To
ok, so I'm the lady who told her man I thought the truck was o.k. -- we just didn't drive it far enough for it to overheat...
since our last post we looked under the hood of another same model truck and the radiator is the same as hers, but it's a v-6
we flushed the radiator in an attempt to un-clog any ports, then put a block sealer in with the same results, then replaced the bottom radiator hose because it looks like it was old enough to collapse.

motor still sounds good, oil pressure is good; the body and frame look good

don't have a pressure-tester- lead man at work made one one time out of a bicycle tube, but I forget now how he did that, plus we would have to remove the radiator to test it that way anyway,and I'm afraid that without a guage, I would over pressurize the radiator and cause it to leak

do parts houses rent pressure testers?

P.S. The seller sold us his problem,as much as I hate to admit it

I can't let this truck beat me. That's what's going on now.



ms grease monkey
Novice

Jul 26, 2008, 11:14 AM

Post #9 of 18 (3781 views)
Re: truck overheating Sign In

damn


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Jul 26, 2008, 12:01 PM

Post #10 of 18 (3771 views)
Re: truck overheating Sign In

There's an upside to this scene. This is a known good engine by design. Head gasket still needs to be verified as the culprit or a crack and both are unusual with my experience with this engine - granted most of them 60s and 70s! They've been around a while!

Crysler did have a time of using inferior "freeze" plugs that rusted and radiators that plugged up faster than some others. Freeze plugs would not cause the bubble but would be leaks.

The pressure testing will help a lot in pinning down the diagnosis. As JIM said they are rentable at some parts places - some free now with deposits to cover loss of course.

If this problem is known get some details. A maybe is that it froze with just water in it at one point and if you find out that might have happened some careful checking of block and heads would be in order - otherwise I never heard of these "cracking" once known ok from new.

Keep at it,

T



ms grease monkey
Novice

Jul 26, 2008, 12:14 PM

Post #11 of 18 (3769 views)
post icon Re: truck overheating Sign In

truck has not run hot yet at an idle will only run hot when it drives
had to idle for three hours to use the block seal (but kept it cool running the hose over the radiator, but I don't think it wouldh've run hot anyway... it only runs hot when it's driven )


(This post was edited by ms grease monkey on Jul 26, 2008, 12:15 PM)


ms grease monkey
Novice

Jul 26, 2008, 12:38 PM

Post #12 of 18 (3765 views)
Re: truck overheating Sign In

I used to use a pressure tester to find radiator leaks, am I to understand that I could detect air in the cooling system with one? There are no water leaks in the system whatsoever. thanks


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Jul 26, 2008, 1:39 PM

Post #13 of 18 (3764 views)
Re: truck overheating - Pressure testing system Sign In

Behaving at idle for a long time suggests the radiator oR fannage thereof could be the trouble.

Pressure tester/testing: This leak if a leak at all I suspect is high pressure combustion gasses getting thru a gasket or whatever into the cooling system. It would look like "air" and rise to the top as thing go. The whole cooling system is pressurized with pressure tester just as the radiator cap would do except you are applying it at will and not just expansion of coolant from heat. The same tester if you pre warmed the engine up such that expansion was about done could be removed or pressure released, put back on and you might see the pressure continue to rise (same would be with a good radiator cap back on) and you could release slowly and see if that cycle continues in front of you - a bad sign if pressure keeps creeping up on its own. DON'T ALLOW PRESSURE WITH A TESTER ON AND VEHICLE RUNNING TO EXCEED THE SYSTEM'S RATING WHICH IS ABOUT 16 LBS.

Understand the system may not leak at normal pressures backwards to combustion when checking but might. A wet spark plug would be found if so or white smoke out exhaust, check oil too. There is a risk of coolant entering the combustion chamber and causing hydraulic lock of a cylinder!

The pressure of just compression, never mind combustion is 150ish and who knows exactly how high what spot gets combustion pressure which is much higher. The gasket or flaw might only pass bubbles then.

Note: I think you understand that air isn't a good coolant. When in with the anti-freeze/coolant it doesn't exchange heat very well at all. With excessive air the heater won't work while it's overheating!

The whole reason for a pressured system is to allow the normal 212F boiling point to be raised almost exactly 3 degrees F for each pound of pressure system will allow. Re: Plain water with a 15 lb of pressure will not boil till 257 degrees F. Hence it can continue to transfer heat at the higher temp, climbing a hill, pulling a load, high outside temps etc., and stay in control lots longer than without a pressure system.

Side note: Pressure systems are just a way to get more out of tighter quarters and smaller radiators in vehicles. Way back in the "Flintone Era" they just made radiators so big it didn't matter and vehicles were big enough to handle it :-)

Got it with the pressure test? If not hit back and I'll try harder,

T
WARNING! RELEASING PRESSURE ON LIQUID THAT IS HOT CAN ALLOW IT TO "FLASH BOIL" AND CAUSE SEVERE INJURY! USE ALL CAUTION WHEN REMOVING A RADIATOR CAP OR WHEN TESTING WITH A PRESSURE TESTER WITH A WARMED UP OR ESPECIALLY HOT ENGINE WHILE APPLYING AND RELEASING PRESSURE. ANYONE READING THIS - IF IN DOUBT ABOUT WHAT YOU ARE DOING THEN DON'T - AND GET PROFESSIONAL HELP.



(This post was edited by Tom Greenleaf on Jul 26, 2008, 1:51 PM)


Fant
Novice
Fant profile image

Jul 28, 2008, 2:19 AM

Post #14 of 18 (3748 views)
Re: truck overheating Sign In


In Reply To
I guess it's radiator that is not in its right place, check your fuel as well Wink



(This post was edited by Fant on Jul 28, 2008, 2:22 AM)


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Jul 28, 2008, 5:39 AM

Post #15 of 18 (3744 views)
Re: truck overheating Sign In

Fant - what thread were you quoting?

T



Fant
Novice
Fant profile image

Jul 29, 2008, 2:55 AM

Post #16 of 18 (3736 views)
Re: truck overheating Sign In

It was magnum22's Smile but now I see, I have done something wrong and I don't know how to quote it as I'm a newbie here. Yesterday was I tried my first post, lolWink. By the way, glad to be a part of the community!


ms grease monkey
Novice

Aug 28, 2008, 4:39 PM

Post #17 of 18 (3647 views)
Re: truck overheating Sign In

truck stopped overheating with thermostat removed.Someone suggested that the fan was rotating the wrong way. tried to find one that would fit a 318 that turned counter-clockwise- couldn't. , but something is still wrong with the truck, right? You should not have to take a thermostat off to run a vehicle, should you?


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Aug 28, 2008, 5:36 PM

Post #18 of 18 (3643 views)
Re: truck overheating Sign In

May I suggest you start a new thread - this one is pretty screwed up now??Crazy

Properly rotating fan on a 318 shouldn't be difficult and not sure it's easy or possible to mix up. Just look at it. Can blades of the fan be mounted on a fan clutch backwards? Dunno first hand right now but a glance would tell.

Taking a T-stat out isn't a solution at all. Better off with one installed stuck open than none as water flow gets screwed up and rear of engine can run hot undetected where gauge sensor is located up front so correct that asap,

T







 
 
 






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