So last August I had diesel in my coolant. Which caused the large donut oring on the intake manifold to get eaten up and a large coolant leak. It also affected the oring on the thermostat, and the one for the metal tube on top of the water pump and the water pump. Cause was cracks in two of the injector bores which I had repaired and reinstalled the heads and everything else.





So after I had it all put back together I stuck the hose in everywhere I could with the thermostat removed and the truck running and spent an entire day flushing. Then put new CAT EC-1 in and all has been good until yesterday when I spotted a puddle of coolant on the ground. So I crawled under and it is coming off the front and rear of the passenger top side of the motor just like when the intake donut let go just not as fast. So today I drained the block and the radiator and poured all the coolant into clear jugs to see if I had diesel in the coolant again. Also it has not leaked much because the degas bottle was still at the bottom of the full mark like it should be. Here is a pick of the coolant.


So there is no diesel in coolant. So my question is could there be enough residual diesel in the coolant to eat away at the oring again. I do not believe it is pinched because I am real picky (****) about doing things right. And with coolant leaking from where it looks like it has to be that oring again. Sorry if this was long winded just figured I would give the history of the problem. Any thoughts. Thanks.

 

I doubt there is still diesel left in there after a day of flushing.

If you still have an egr cooler, check the little orange or blue hose.

If you have an egr cooler delete, check the silicone hose between the delete and the oil cooler.

 

Did you use something like simple green when you did your flush to get the diesel out? It probably wouldn't take much residual diesel to eat the orings.

 

I installed a new blue hose.

 

No I did not use simple green or anything like that. I thought about that after I was done flushing and had the new coolant in. And I am mad that I did not think of that at the time.

 

How much simple green do you use when flushing the cooling system and is there more than one type of simple green.

 

1/4 gallon should do it. I would use the regular simple green. I think there is 2 types, the other one is more powerful.

 

I just put 4 cups of simple green concentrate in and ran it for an hour. How long do you all think I should run it to clean the system. Thanks

 

Did you normal or high idle the truck? I like to let them high idle for at least an hour to give it a good "scrubbing" and to make sure the thermostat stays open.

 

I have not done the high idle mod yet so just let it idle normal With the thermostat out. Even drove it slowly for a two mile round trip keeping the Rpm's under 2 k.

 

I think you should be good.

If a truck has electric seats, I'll put a wood block between the seat and fuel pedal and bump it up until I get the right RPM's. Saves on the arthritis--LOL.

 

Thanks, I will start flushing the sg out tonight and hopefully tear into it tomorrow and find out what is leaking from what it looks like it has to be the intake oring or the blue hose but i am very curious to see what it is.

 

So I get it apart and all orings and seals look good. This sucks I guess I will reseal the oil cooler my delta is good. reseal the egr cooler and metal tube from the heater, new blue hose and put back together. With it leaking down the back of the motor and the front of the motor there is not many things it can be. If anyone has any insight I would appreciate it. Thanks

 

The leak has to be somewhere around the oil cooler.

 

I agree 100% it just sucks that I can't pinpoint it exactly. So I just bought an oil cooler reseal kit, egr kit, turbo kit and metal pipe to front cover oring and will put it back together and see what happens. I need to get a cooling system pressre test kit for this stuff. I could have rented one but I was pretty sure where it was coming from or at least I thought I knew.