2015 Peterbilt with Paccar MX 13 losing coolant

Small leaks can be common and hard to spot. Start by snugging up all hose clamps. Look for cold leaks when the truck sets overnight as hoses and seals contract.

Some water loss is acceptable over time. Water evaporates through silicone hoses, but not rubber. All Paccar trucks are factory equipped with silicone hoses. Normal loss would be around a quart a month during normal daily operations.

 

Learned something new today
Thank you

 

I know a few guys who use to top up coolant often because the low coolant sensor in the overflow tank was so finicky . Turns out that they expand and lose coolant then when cold it shows low and trips light occasionally but once warmed up it goes back up in tank they were just spitting the same amount they added out the overfill hose .

 

Its common. I have a 2014 Peterbilt Paccar MX13 .....does the same thing.
I had a clamp bust so I carry extra clamps now. They are around $10 ....they become lose time to time.
I'm over the road west to east coast driver and this Pete eats alot of oil and coolant. Especially during summer when its hot.
Just make sure your cap is on tight and look for small dribbles underneath or signs of dried coolant where there is a leak if applicable

 

Look for the return coolant rail at the bottom of your heater corn which on the right passenger side front. (heater corn connect to it with a rubber hose). It is a metal rail over time salt will destroy the rail rust to the end of other rubber hose and cause it to have small leak, and the coolant turn into vapor on rail soon due to heat. Good luck. Don’t wait until it flooded

 

I have two friends that say that the Dpf system uses a little of it but I have no clue if that’s true

 

DPF uses coolant? Not true.

The DEF system uses coolant for tank heater and to cool the DEF doser on EPA 13 and DEF Pump on EPA 17.

 

its tru....there are 2 doser valves....the (High Carbon) which is on the engine side and then the 2nd doser valve which on a Paccar is on the passenger side behind the fuel tank so you will have to slide under the truck....for some reason the Kenworths 2nd doser valve is on the outside of the right side fuel tank so you would have to remove the side faring to reach it

with that being said the 2nd doser valve has 2 coolant lines and one DEF line.

you will have to follow the coolant lines because sometimes they leak either from the doser area or in the middle of the line where there is some kind of hard plastic coupling that directs the flow of the coolant...its pretty simple to find.

also you look under the truck to see if there is a leak and maybe you can pinpoint it

the leak will usually be on the right side of the truck as are the coolant lines

 

Use as in consume? No. The emission system should not consume coolant during operation.

Use as in utilize? Yes. Coolant is utilized in the operation of the emission system. EGR cooler, DEF tank heater etc.