Seeking thoughts and experience on cooling system PM for the D3. Having owned D1s/RRCs and an E46 BMW, I'm sold on preventative maintenance in this area, but honestly after a few years and 25k miles I haven't done anything for my D3 except for belts/pulleys and a brass bleeder T. Currently at 155k miles. The housing was done by a prior owner (dealer record) at 107k, and the expansion tank at 97k.

I am tempted to get the kit and replace all the cooling hoses which are original, but I can't say I feel much urgency about it. Would be pretty soon to do another housing I guess, but would probably replace the housing and t-stat at the same time.

I do take the truck on trips and out into the woods so I want it reliable, but is it reasonable here to just keep an eye on things vs. a big refresh? Doesn't seem that cooling system failures are all that common on this platform. Talk me out of it

TIA for your opinion.

 

Besides the t-fitting, the heater core is a weak point when it comes to failure. Not a leak issue, but it acts as a cooling system filter. The core is always flowing 100% of the time. And the design is poor. Hot coolant enters on the upper right side and cooler coolant exits at the lower right. So what happens is the lower left side tend to collect garbage in the system. The result is the driver side gets less and less heat until there is none.

So a good preventative measure is to disconnect the core at the firewall and flus it out a lot. A citric acid flush can also help clean out junk and keep it working. I have been putting things off, but I will be doing a full acid flush of my truck, not just the heater cores.

 

Thanks Dakota. I should have mentioned, I did replace the heater core as well (how could I forget that joy??).

I take it from the general lack of response to this thread that cooling system PM is not high on many other folks worry lists either. Be curious to hear from someone who bought the full kit from AB and replaced them all. (what prompted, and how was the job...)

 

Yeah the only really concern the crossover housing, which has the t-stat. I carry a t-stat out of normal overland "things to have" on a trip. But beyond age maintenance, its not a system known for any real weak points. Use the proper fluid (not green) and you are fine. Even the water pump is pretty robust lasting most folks well past 200k miles. Some, less of course. Another thing I carry as a spare but at 160k miles, I still have the original installed.