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Discussion Starter · #1 ·
Ok so i have been chasing the coolant leak.

I did have a crack in radiator and have replaced that. I read on one of these forums that your coolant can start to boil over as factory degas cap didnt hold enough pressure. I had noticed drips on passenger valve cover and degas bottle had burnt looking coolant around cap.

I replaced the cap with bigger spring and leaking around cap has stopped however all the tiny leaks have became bigger... presuming the increased pressure is pointing out the problems already present.

So far i have replaced lower hose, degas bottle and changed to different cap with bigger spring. Also replaced radiator, hoses on driver side

New leak appearing from passenger side hose that starts from right by alternator and runs back towards firewall. I believe that goes to heater core. Every parts place i have tried said this hose goes to the bottom of the degas bottle. That is not what i am looking for.

Can someone look at photo and tell me what this part number is?

I am not sure if it is one assembly of if all these pieces are seperate.

It appears to be a simple fix if its just the hose. There is no drips in passenger floor, no fogging or steaming of windshield and heat works fine so i am assuming its not heater core itself just these hoses.

I have read the hoses have special clips and o rings and so far nothing has been as easy as it looked. LOL

Any help is appreciated.

Lori
 

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You need to monitor the pressure in the degas bottle. It could be that you have an issue with EXTRA pressure in the system - which can cause leaks.

The way the degas system works is that the fluid (coolant) expands as it heats up, and that creates the pressure in the degas system (compresses the vapor space in the degas bottle). The degas pressure should be around 8-12 psig due to the normal expansion of the coolant volume (assuming proper level and proper engine temperatures). The factory cap is designed (relieves at 16-18 psig) to have the proper pressure and as long as it hasn't failed (and you don't have a leak), it is perfectly fine for properly operating the cooling system. You should not operate with above 18 psig or you will CAUSE more leaks to happen. Yes, sometimes the degas cap can get weak, but that is not the big issue that the PSH video/web-site claims it to be (and you certainly don't want MORE pressure in the degas bottle than 8-12 psig).

For the part number, IIRC it depends on the model year of the truck. What year truck do you have?
 

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You need to monitor the pressure in the degas bottle. It could be that you have an issue with EXTRA pressure in the system - which can cause leaks.


For the part number, IIRC it depends on the model year of the truck. What year truck do you have?


I happened to catch 2004 on the valve cover. If it's got the plastic heater valve, it should be 5C3Z-18472-F. The version without the valve is 3C3Z-18472-AA. Also, the Excursions are different number; these numbers are for the pickups.
 

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Discussion Starter · #5 ·
Thank you. Been out of town just got back to this....

So far i have contained that drip from the hose..which i now believe to be called the HVAC hose with believe it or not.....Duct tape covered with Vinyl tape.

Still looking for the hose #.

How do i monitor pressure? The gauges are always within the normal range,
 

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Discussion Starter · #9 ·
it is an Excursion. 6.0l Diesel 309000 miles 2004 with 12/03 MFG date
essential pieces vin u45p44eb
 

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Discussion Starter · #11 ·
Thanks so is the valve itself part of the hose assembly? It looks like it in the phot so id only need the hose assembly correct if i want to replace the whole thing.
 
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