Radiator Expansion Tank Hose

[rynil2000]

Hey everyone, just want to say thanks for all the helpful information through the years, but now I have a question that I have been struggling to find an answer.

I am working to solve a coolant leak issue in my 2002 Sport Trac. Over the summer, I replaced the radiator, upper and lower hoses, the expansion tank (washer fluid combo unit), and the thermostat housing. However, my truck still regularly looses coolant from the expansion tank due to the small hose being old and loose on the new expansion tank barb. You can see a wet mark below the barb and watch it drip.

What is the recommended replacement size for this hose; inner diameter and length? I cannot find the information online and Ford parts does not stock this component any longer. I am going to order a high-temp replacement via McMaster.

 

[Paul Fithian]

Take your old hose to any auto parts store and have them cut a new one from one of the spools of various size hoses they have in stock.

 

[koda2000]

If I had to guess I'd say it's either 1/4" or maybe 5/16" (probably 1/4"). As said there's nothing special about it and any auto parts store sells it by the foot.

Have you replaced your thermostat housing yet? That may also be where your coolant disappears to. Super common issue with the SOHC V6 engines. A metal replacement is now available from Austekk for about the same price as the problematic plastic housing.

97-01 Explorer Mountaineer 4.0L SOHC Aluminum Metal Thermostat Housing Kit | eBay

 

[rynil2000]

Thanks for the replies. I guess I've never noticed the bulk hose section of the auto parts store. I'll have to check it out.

Koda - I did replace the thermostat housing recently. Thermostat went bad, so it was a good excuse to replace it all.

 

[koda2000]

Thanks for the replies. I guess I've never noticed the bulk hose section of the auto parts store. I'll have to check it out.

Koda - I did replace the thermostat housing recently. Thermostat went bad, so it was a good excuse to replace it all.

The bulk hose is kept behind the counter at auto part stores. Ask.

 

[rynil2000]

Thanks

 

[Paul Fithian]

See 4.0 SOHC Metal Thermostat Housing Comparison

 

[imp]

If I had to guess I'd say it's either 1/4" or maybe 5/16" (probably 1/4"). As said there's nothing special about it and any auto parts store sells it by the foot.........

@koda2000
If the '02 ST has the same pressurized tank system as my '04 Ex, just any old hose is a mistake, as the tank is pressurized to 16 psi. Vacuum hose, for example, with no braid in it will likey go away pretty quickly under pressure. I like to use 30-R7 (fuel & emission hose, not for fuel injection) almost exclusively. Not cheap, but less than 30-R9 F.I. rated hose. imp

 

[koda2000]

@koda2000
If the '02 ST has the same pressurized tank system as my '04 Ex, just any old hose is a mistake, as the tank is pressurized to 16 psi. Vacuum hose, for example, with no braid in it will likey go away pretty quickly under pressure. I like to use 30-R7 (fuel & emission hose, not for fuel injection) almost exclusively. Not cheap, but less than 30-R9 F.I. rated hose. imp

To my knowledge the '02's coolant tank is not pressurized. It should be the same un-pressurized tank as was used in the '01's.

 

[imp]

To my knowledge the '02's coolant tank is not pressurized. It should be the same un-pressurized tank as was used in the '01's.

@koda2000
Then any decent hose is good. I wonder when the pressurized tank came about? I am a bit confused, not aware Sport Tracs are so different. I'm thinking all Gen 3 Exs have pressurized. I like it better, as it eliminates the two-way valving on the radiator cap, actually eliminates the rad. cap altogether, mine has none! No filler neck. The concept was introduced in 1958 with Ford's FE big block, and might also have been used with the old 312 Y-blocks then. They used a brass tank bolted to the thermostat outlet hole of the intake manifold.

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Here's a "cammer":

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[gtyates]

On the 2001-2005 Sport Trac the hose to the overflow tank is not pressurized. The overflow tank is just that, an overflow tank. On the regular Explorer from this same time period the system is different and the tank is pressurized as it is part of the cooling system. FYI.

 

[boominXplorer]

Put a good zip tie or hose clamp on it and keep it moving. I notice after-market radiators having slightly smaller outlets quite often.