I have swapped a 4BT Cummins into my 2003 Expedition. The heater hoses are in the stock location, near the PCM. The hoses are above the turbo and exhaust manifold.


View of the stock heater hose assembly, next to the exhaust manifold and above the turbo.

Yesterday I was sitting in traffic when smoke started coming out from under the hood, which is never a good sign. About then the light turned green, so I went through the intersection and pulled into a parking lot. I saw what appeared to be intermittent smoke plumes coming off the turbo, like there was a dripping oil leak from the oil fitting. It was a hot day (about 95F), so the AC was running, which runs the electric cooling fans too. But sitting at a stoplight, this does not remove much heat from the turbo section of the engine compartment.

Seeing no fire and no major oil leak, and since I was only a couple miles from home, I went home, parked it and let it cool off. When I looked more closely at it, I find coolant under the turbo area, on the starter, engine mount and sway bar. At first I thought oh-no, blown head gasket. but I could not see any leak from the head with the engine running. There is no coolant in the oil, and no hydrocarbon smell in the de-gas coolant tank. Looking at the heater hoses, I see evidence of a leak at the firewall fitting. You can see it in the photo below, the green crust that is a little out of focus on the right-side hose.



I am wondering if it is a plastic or rubber push-to-connect that just relaxed enough to leak when hot. Today is a little cooler and there is no problem. Anyone have this problem too? I looking into getting an insulation blanket for the turbo, and wrapping the exhaust manifold with fiberglass insulation tape. Any other ideas?

Thanks in advance,

CR

 

The Quck Lok OEM connectors are almost all plastic including the hose ends as well as the locking tabs and o-ring type seals. Given the heat off the turbo I wouldn't be a bit surprised if that's not affected them in some way.

The good news is those can be replaced with Dorman parts: Dorman Products - 800-404. They can also be cut off and clamped to the heater core tubes with standard worm screw band clamps.

HTH

 

Thanks JWA,

I will get some on order and try them out.

CR

 

When installing new quick disconnects to heater core tubes, does the clip and o-rings have to be transferred to the heater core tubes, or will the whole assembly snap in over the tube beeds?

 

If your disconnects are like those on my 1997, the whole disconnect assembly with hose slides onto the heater core tube and latches over the bead. In other words, the stackup of internal parts should be inside the connector housing before pushing onto the tube.

 

Here's an image of a '00 E250 heater core tubes---all others are similar with the only real difference being diameter of the tubes.




Complete Quick Connects installed:

 

Well plan A did not work out that well. The Dorman fittings were for 5/8" hose, 3/4" heater core tube stub. I ordered them from Rock Auto, and that web site listed the same part number that JWA did. When I took the first fitting off, it cracked into a couple of pieces, so obviously it got a little hot and brittle. Once it was off, it was clear that the heater core tube stubs were 5/8" OD. Somehow the wrong part is being published, but there's always plan B.

Being a Sunday afternoon and no handy 5/8" hose x 5/8" tube stub fittings, I reverted to plan B. I put 5/8" ID silicone hose on the stubs and clamped the hose behind the bead on the tube with a worm-drive hose clamp. I cut off the crimped collar on the factory tee fittings and connected the silicone hose to the barbed fitting with another worm clamp.

So far, so good. I ordered a turbo blanket and some fiberglass wrap tape, which is not here yet. Eliminating the plastic fitting and covering the heat source should solve my leak problem on hot days. I will report back either way.

Best,
CR

 

How do you like that 4TB in your expedition? I love that cummins, we have the same motor in our woodchippers and stump grinders. Is that after cooled? Using coolant or did you but in a intercooler, would love to see engine compartment pictures. Thanks

 

Hi David,

I really like it. I have had it as a daily driver for almost four years now. I get about 20 mpg around town and 23-24 on the hiway. I especially like the torque at low rpm.

There are some pictures on this forum here, and the entire build-up thread is posted at 4BTswaps.com at the link in my signature. Go to the last page for videos.

Best,
CR