Coolant Reservoir plumbing??

**mike_ie** · 3rd March 2013, 09:04 AM

I'm wondering how other Isuzu Countys/Defenders have their radiator system set up.

I'm converting the Defender, which means it has the plastic bottles with the two outlets. A larger 16mm connection that keeps the radiator supplied, and a smaller 8mm connection that I assume is for overflow back to the reservoir.

In the 300tdi, the radiator hose has a big t-piece off the bottom hose that the reservoir feeds, the Isuzu hoses don't have this without cutting hoses.

So what is everyone elses setup? Where does the reservoir feed the radiator??

**Bearman** · 3rd March 2013, 09:30 AM

Mike, the standard setup is a metal overflow tank with a pressure cap and a small hose that joins onto a nipple on the top of the radiator tank on the drivers side. There is also a bung on the top of the isuzu thermostat housing for filling purposes. It is a real pita to fill/bleed. My experience is that it is easier to remove the top radiator hose from the radiator and fill to capacity, tighten it up, remove the bung on the thermo housing , fill the overflow tank, block the overflow outlet and and blow into the overflow tank until all air is expelled out the bung. Start engine and repeat procedure when operating temp achieved.Not sure what radiator you are using but it really doesn't matter as long as it works.

**mike_ie** · 3rd March 2013, 10:19 AM

So there's no second line from the reservoir then to fill the radiator??

**inside** · 3rd March 2013, 10:27 AM

One overflow hose (labelled 3) the outlet at the front of the tank goes to top of radiator.

**Bearman** · 3rd March 2013, 10:31 AM

Correct, the top of the thermo housing is higher than the radiator and the top of the overflow tank so I guess that is why the filler bung is there.

**Bearman** · 3rd March 2013, 10:34 AM

Originally Posted by inside

One overflow hose (labelled 3) the outlet at the front of the tank goes to top of radiator.

Not that one - that is the overflow drain. The radiator one connects to the nipple on the other end of the tank top.

**inside** · 3rd March 2013, 10:38 AM

Originally Posted by Bearman

Not that one - that is the overflow drain. The radiator one connects to the nipple on the other end of the tank top.

I thought that's what I said??

Number 3 overflow (drains to ground) the other goes to radiator.

**Bearman** · 3rd March 2013, 10:44 AM

Originally Posted by inside

I thought that's what I said??

Number 3 overflow (drains to ground) the other goes to radiator.

Yeah, you're right, I just read it differently.

**c.h.i.e.f** · 3rd March 2013, 11:55 AM

What's the pressure rating on the cap ?

**steveG** · 3rd March 2013, 01:01 PM

I had the same issue with mine Mike, as it was a 20tdi that came out.

Ended up connecting the large lower hose on the reservoir to a barbed fitting on the drivers side of the thermostat housing. Just had to remove an existing plug from the housing and screw in the fitting.
Small hose from the top of the radiator connects to the small barb on the tank.

I know its not perfect, and always seems to have air in the top hose with the engine off but I've never had any cooling issues, and don't get funny temp spikes etc so I haven't bothered to change it. Engine watchdog bolted to the thermostat housing hasn't got higher that mid 90's even towing our camper for long uphill stretches around 40deg ambient.

Steve

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