cooling system problem

[Portschy]

the problem only happens when he lets off the throttle, we live in a valley & the only way to get out is go uphill, its a long pull, both hoses have springs the entire length

 

[Portschy]

i am a mechanic & the system has been pressure tested 3 times also cap checks good

 

[MMiller]

Portschy;



I ment no disrespect on the pressure test, I hope that I did not come across that way. I found that if I don't carefully tell someone a procedure the first time assuming they understand what I am trying to explain, I end up having to draw a picture in the end. I am truly sorry for any disrespect. It was not intended.



I guess if it holds pressure then it surely is not got a head gasket leak, which could cause heat problems. I am at wits end on this problem. I hope someone can lead you in the right direction.



Now we have two differnt trucks we are talking about right-JStraw- yours is a 93, and Portschy the one you have is an older non IC engine, right? It sounds like Jstraw's has a coolant leak somewhere that needs pressure checked.



Man I getting confused here I think. We have two differnt trucks here right?



Michael

 

[Portschy]

no thought of disrespect at all, this SOB has me thouroughly cornfused, it never loses any coolant, & pressure tests fine, i have press tested it cold & hot both with the same results,this to me rules out a head or gasket problem, any chance it could have a cyl sleeve ring leaking?? i am not getting any antifreeze in the motor oil or oil in the cooling system,

 

[Paychk]

the t-stats were they Cummins or after market?, also does the truck have the 92 cross flow radiator? or was it changed to one compatible with the 91 engine?



The reason I ask is, when the inter cooler was added in 91. 5 the rad. changed to cross flow and also I believe the t-stat housing and all the rad. hoses changed too. How is a 91 engine (pre-cross flow) hooked up to the new style rad. ? more possibilities has the oil cooler been pulled and checked for flow? has the mechanical gauge been checked for kinked line & verified for calibration?

 

[cerberusiam]

These engines aren't normally sleeved unless there has been damage. No sleeve rings to leak.



Thank you Paychk, I have allude to the same thing you said three times. Is "engine oil cooler" not descriptive enough?



Portschy, I am going to ask one more time then I am done. Where is the temp probe for the gauge that is showing hot? Are you relying on the electric gauge or using a mechanical and where is the probe located?



Temp spikes are not unusual with the electric sender. They are bad out of the box. ENGINE OIL COOLERS can cause problems with flow and cooling. Has it been checked? Is it even there?



Portschy, I am not knocking you but, jeeez, read all the posts, answer the questions, and try to keep an open mind. You asked for help and opinions and you ain't giving much info in return.

 

[JStraw]

MMiller, yes, two different trucks. I changed out the engine oil and transmission fluid with filter. I was relieved to see no indication of coolant in either. I installed an additional temp sender and gauge with the sending unit installed in the T-Stat neck. On the way into work the instrument panel gauge would move to alittle past the 1/3rd mark then drop as the T stat opened. My aux gauge showed 181-183 degrees before the T-stat opened and would drop to 177-174 when it opened. I'm pleased it, (instrument gauge), didn't do a wild climb but still am leary. Unfortunatly, I got to work and could still smell a slight odor of coolant. Tommorrow its time to get greasy.



Guys,Thanks for all the help, ideas and suggestions. I've got alot to check on.

 

[Portschy]

there is no oil cooler on the engine, the mech temp gauge was plumbed in where the stock sender is & at the bleed plug on the front top of the head, the readings on the front of the head were about 10-15 degrees hotter but that is to be expected as it is where the coolant leaves the engine to go to the radiator

 

[Portschy]

the t- stats were both genuine cummins,, the radiator is not a cross flow so it must have been changed with the engine

 

[Philip]

With springs in both raditor hoses. My next step would be to pull that raditor and have it flow tested. I think it has some stoped up cores in it. A fast test would be get it up to operating temps and do a hill climb. Then stop and shut it down and use a infred camera or temp gun and check that core for cold spots. If neather are handy. Use your hand. The places your hand doesn't get burned on are nonflowing areas.



Those down flow raditors weren't rated very good for a cummins appilication.

 

[Paychk]

there is no oil cooler on the engine, the mech temp gauge was plumbed in where the stock sender is & at the bleed plug on the front top of the head, the readings on the front of the head were about 10-15 degrees hotter but that is to be expected as it is where the coolant leaves the engine to go to the radiator

To my knowledge all Cummins B engines in Dodge trucks come with an engine oil cooler, it is integral to the oil filter mount, are you say this was removed? Also you have alluded to bleeding the cooling system & again state the temp gauge was moved to the bleed hole, what bleed hole ?? Could you maybe take some pictures of this engine and post them, something isn't adding up.

 

[BushWakr - RIP]

I have an oil cooler???? !!!! I must missed that class... geezzz I luv this place...



pb.

 

[Portschy]

i didnt realize there was an oil cooler built into the filter adapter, there is no coolant to oil transfer in the system, flow through the cooling system seems to be fine, the bleed plug is on the front of the head on top, right above where the t-stat fits in the head, 3/8 square drive, i would take a pic but i have no digital cam & the pickup is not here at my shop right now, agianst my judgement he is driving it

 

[JLEONARD]

Portschy... I'm disappointed I forgot to suggest this right off the bat...

I assume you have a non-contact temperature gun. If not you shoud... it is a terrific tool )

This should let you find where the hot spot(s) is.

You can check the radiator for flow, check the oil cooler, check the heater core, check for air pockets and hot spots in the head, etc.

That is what I think I would do next... shoot the whole system looking for temperature inconsistancies.

Hope this helps a little.

Jay

 

[JStraw]

Slap me silly... paint me purple... spank my butt and call me a queer. Dumb luck finally showed me the problem. I was 40 miles into a 325 mile trip Friday night when the temp shot up to 205. I exited the next rest stop and refilled the radiator. The temp dropped to 177 and stayed that way the rest of the journey. Bad radiator cap Oo. I found and tightened several hose clamps yesterday and just installed the H. I. D headlight kit. Tommorrow I do another 325 mile trip to put it all to the test.