All,

My truck has recently developed the infamous right hand side coolant leak. Based on what I was seeing, I went ahead and installed a new thermostat housing gasket, and lightly coated the housing, as well as both sides of the lifting bracket, with RTV before putting it all back together. I also went ahead and installed a new upper radiator hose, as the old one was cracked. With that, I took a spin to to grocery store, and noticed dripping coolant when I got to the grocery store parking lot. It again seemed to be coming from underneath the thermostat housing.





A few days later, I took the truck down the highway. When I arrived at my destination, no coolant was leaking from underneath the thermostat, but was now only seen by the water pump mounting.
It almost looks to me like the head is warped a bit in this picture:



But when I had the thermostat housing off, all looked alright:




So, what are some thoughts on this? I tend to think that I'll be doing a head gasket soon. I should add that the engine oil doesn't appear to have coolant in it, and looks perfectly normal. I also did a few combustion leak tests, and all came up negative. Any input is appreciated... Thanks!

 

If your able to look at a head and with your eyes, determine your head is warped you have one sharp eye.

Who's thermostat gasket did you use?

 

Looking at that last picture, I believe I would clean up the head before I put another gasket on, you need a clean flat surface to seal properly.

 

I used a genuine Cummins thermostat gasket, and scraped all mating surfaces thoroughly before putting it all back together. I also put a very light coat of RTV on all mating surfaces.

 

Sorry, but picture #2 shows you're not cleaning the surfaces properly. Both surfaces should be shiny chrome clean when / before you put everything together.

I don't use any RTV on my thm housing, and it works fine and can be disassembled without much fuss.. I also use the cummins rubber seal and THM

 

Hey NJTman, what is the best way to go about getting these surfaces that clean? as mentioned, I went at it with a scraper for awhile, but they certainly were not mirror clean when I put it back together. I appreciate any advice!

 

Best is a Roloc 2 inch pad in an air powered 90 degree die grinder
https://www.amazon.com/Roloc-Disc-Pa...die+grinder+3m

I use the medium discs on most stuff, but here is what the coarse discs look like.https://www.amazon.com/3M-07480-Coar...rds=roloc+disc

The tool it fits in, https://www.amazon.com/Ingersoll-Ran...inder+air+tool
I guess you could try a drill. Difficult it would be getting in tight spaces

 

i wouldn't use this^^^^

creates too much heat, can take material off the block leaving an untrue surface. it may have worked for you, but not great advice.

I'd clean it real well manually as you've done and then wire brush it by hand or carefully wire wheel it with a die grinder.

 

Every automotive and diesel mechanic I've ever known used that setup. Over 25 years as a mechanic, and I've never damaged anything I've worked on with it. That's why I said in my post to use the medium or fine grade roloc pads as the coarse are for very aggressive types of removal jobs.

Common sense dictates which types of surface material gets which grade of roloc wheel. Its like anything else in this world, if you are not careful with what you do, you can destroy anything with any unfamiliar tools.

Post edited by Admin

The OP can make the decision on his own given options posted here. If he has any concerns, I suggest you tube and search roloc disc in the search bar

 

Has anyone realized yet that 100% antifreeze is what works best on these systems?

I have it on good authority from a gent who has been successfully been using it for 25 years.

Gotta love folks with 25 years of wrenching expertise.

Educational link here on DTR - https://www.dieseltruckresource.com/...-326125/page2/

 

That's great, you came to your senses finally, way to go. That is getting closer to 40 years of experience by the way ...Mark

 

I disagree, I wire wheel in die grinder will be more likely to do damage as it has less surface area and generally buger there will be more heat as there is more surface velocity. and the and the smaller footprint is way more likely to damage part that a larger flat surface. I have used the rotolok discs for many years with no ill effects. just keep them moving.

 

I feel so lonely stuck out in the rain.

 

I love you T-man and you don't even have to love me back. Can't we all just get along? ...Stirring the pot...Mark

 

MMMM stirring the pot. beans and cornbread.