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micheal

300 Tdi small hose from ccolant reservoir

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Hi guys

Looking for a bit of help from disco owners please.

I have a 300Tdi from a disco in my 78 range rover. The guy that put it in blanked off the small bore hose from the reservoir. Could some one have a look under their bonnet and tell me where this hose is supposed to go please?

My engine is mounted very high to clear the steering box but it means that the reservoir has to be full to the neck to ensure that the thermostat housing is full to the bleed plug. Can anyone see any problems with this lack of expansion capacity?

All advice greatly recieved.

Micheal

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Yes :)

I cant give you scientific or engineering reasons unfortunately, but the expansion tank must be filled half way for a reason I assume!

The small bore pipe coming from the front of the expansion tank runs an 8" hose to somthing called the Expansion Tank Ejector Valve, basically a three way valve which connects via two more small hoses to the small pipe on the stat housing and the small pipe coming out of the rad just above the oil cooler fittings. Not entirely sure what it does if I'm honest, apart from provide a two into one join in the cooling system but hope that answers your question to some degree.

Stu.

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The tank MUST be only half full to allow for the coolant to expand and maintain the operating pressure - 15psi - water will not compress but air will.

Okay the small line is an air bleed, even though you may start off with air in the thermostat housing the air will eventually bleed off into the reservoir -- with a resulting drop in coolant level. A quick trick is to loosen off the top hose clamp connection at the thermostat housing and blow into the cap and pressurise the reservoir until coolant comes out of the hose, then have an assistant tighten the loosened hose clamp, if you have no air leaks the natural vaccuum will prevent the coolant from draining back into the reservoir tank. Top up the tank to the half way level.

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Thanks for that guys.

I'm going to tee that pipe into the line that goes from the top corner of the rad to the thermostat housing. Not sure about the Expansion Tank Ejector Valve. Do you have a part no. for that?

Do you think that trick would work by using the bleed plug on top of the thermostat housing Nstead of the pipe as It's difficult to get assistance but I think I could tighten the plug while blowing in the reservoir myself (who says men can't multi task) :i-m_so_happy:

Should be nice and tasty now I put in a load of antifreeze last night.

I was envisaging cutting a power hump in the bonnet to accomodate a higher expansion tank :unsure: which might ruin the lines of the bonnet some what.

Micheal

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AFAIK all 300 Tdi's, Disco, 110, 90's has the expansion ntank mlower than the thermostat housing, hence the three thin coolant pipes going into the 3 way valve for auto bleeding. Many auto bleed valves leaks so a Y-piece gas pipe fitting goes in, that means carefull manual bleeding when re-filling the cooling system. Half full expansion tank is a must.

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