Thermostat bottom bypass hose

[cab]

Hello,

Is this hose a Nissan item or just a chunk of bulk hose? thanks

[Carimbo]

I don't see how it's molded in any special way, should be able to replace it w/ a short piece of bulk (sorry don't know the size) coolant hose. OEM hoses on these engines are reputed to be long lived, but this one on my car feels too soft so I will be replacing it soon.

[asavage]

I'm just sure it's some odd diameter, but it may be available aftermarket and OEM.



Hose, 14055-V0700, $9

I haven't looked recently: can it be replaced without removing the thermostat housing?

[cab]

I haven't looked recently: can it be replaced without removing the thermostat housing?

Thanks for posting the part numbers. My wishful thinking says yes, gut feeling says no.

[240ZD]

I was doin' some thinkin', and perhaps it would be good to rubber-cap the two bypass pipes and install a normal thermostat, just to make sure all coolant is going through the radiator.

Does the engine really heat up that much faster with the bypass system?

[asavage]

Does the engine really heat up that much faster with the bypass system?

Yes. The bypass design prevents hot spots, because if the WP cannot circulate (blocked by t-stat), hot water does not flow by the t-stat -- water remains cool there, no flow, even if the rest of the head/block water is at or above setpoint.

By circulating the water in the head and block, the block heats up uniformly and as soon as the bulk of the water reaches the setpoint -- or close -- the t-stat "knows" about it and begins to open.

Designs without specific bypass hoses exist -- my 3.0l Aero is one such critter. It uses a non-valved heater core to perform the bypass function. But the Maxima has a valved heater core. The bypass design is needed.

[LD28 Owner]

The marine engine integrates the thermostat housing with the water cooled intake/exhaust manifold. The thermostat bypass is a molded, 1" ID hose.

My plan for replacing the hose is removing the bottom bypass inlet and replacing the hose and inlet gasket (part #13050-50L10).



I would assume (I know, that's dangerous) that the automobile LD28 bypass hose would be 1" ID as well.

How accessible is the bottom bypass inlet in the automotive setting?

Jim

[cab]

Picked up the replacement bypass hose from the local nissan dealer; 15 bucks and 3 days later for a 4 inch chunk of metric coolant hose that feels softer/thinner than generic heater hose. My thoughts are, save your money and skip the factory hose and go with the bulk flaps hose.

[LD28 Owner]

Cab,
Is that hose about 25mm in diameter?
Jim

[goglio704]

This is from an old thread in the Peddle or Procure section. Quoted here for organizational purposes...

LD28 Cooling system hoses part numbers, from the Dec-1985 Parts Catalogue. Some part Nos. may have been superceded, and some hoses are very different from the L24e.

(This is unbelievably difficult to cull out of the Catalog; the hoses are spread across a LOT of different sections.)
----------------------------------------------------------------------------------

Upper Radiator                                                                   21501-W2403, $12                        
Lower Radiator                                                                   21503-W2403, $16
Upper heater hose (engine side of firewall, at firewall), to 6-82               92400-W2400, $6
Upper heater hose ("inlet", engine side of firewall, at firewall), 7-82-on      92400-W2500, $7
Lower heater hose ("outlet", engine side of firewall, at firewall)              92403-W2501, $7
Head-to-Oil Cooler                                                               21306-V0700, $9
Oil Cooler-to-Inlet (Inlet?)                                                    21307-V0702, $12
Bottom bypass hose (under thermostat housing)                                   14055-V0700, $9
90° hose on banjo fitting on top of water inlet to water pump (under PS pump)   13514-W2501, $8

----------------------------------------------------------------------------------

Try as I might, I can't find all the other little hoses around the IP. Maybe Steve can have better luck, but I've struck out.

I've left out the heater hoses on the passenger compartment side of the firewall. Let me know if you want those too.

[later edit]
Hoses for heater on the passenger compartment side of the firewall.

Hose, firewall joint to valve (7-81-on)                                          92406-W3200, $7
Valve ("Cock Assy - Water (for heater)")                                         92240-W2100, $22
Hose from valve to heater core -- shown, but no key number or part number.
Return hose from heater core to firewall joint  (7-81-on)                        92407-W3200, $7