Thermostat Bypass?

[silicon_toad2000]

Heyya guys,

hope all are well.
I had a question about a bypass hose I have on the thermostat housing, seems to allow the coolant to bypass the thermostat. I'm in the middle of winter here and I only have a short run to work and the poor thing never gets off the cold mark.
I was thinking about blocking it off but I thought I should check for opinions first.
I couldn't find an explanation of why it was there in the manual and I did a search and came up with no clear reason for it.

What's it for?

 

[cruiser88]

Just how cold?

 

[silicon_toad2000]

Not as cold as the winters most people have to put up with, never (very rarely) gets below freezing.
By the time I get to work the temp gauge has moved about 1mm off the bottom of the gauge. Takes about 10-15minutes to get to work, mostly 80kmph.
I get the feeling if I block off this hose the engine will warm up quicker and be better for it.

 

[ntsqd]

Sign me BT, DT on this one.

I tried various things with this on a Ford that I had that also took a long ways to get warm.
Blocking it off is not a good idea. Allowing a little flow keeps the h2o pump from cavitating, which would start to erode the pump vanes. Then it wouldn't cool so well when hot either........
On the Ford I made up a way to jet the by-pass so that I could see if reducing the flow made a difference, and how much of a change in restriction had how much of an effect.

The end result of all of that testing was no change in the by-pass at all and a piece of cardboard in front of the warmest 1/3 of the radiator (cross flow type) during the cold months.

 

[Wile E Coyote]

I don't see above freezing temps as reason enough for drastic warming measures to be taken. IF this is a cruiser motor, then perhaps the bypass hose isn't the problem. The o-ring inside the t-stat housing, on top of the t-stat; If it's torn, improperly installed, etc, it will allow nearly full bypass of the t-stat. This will cause over-cooling and the only fix is to get a properly installed o-ring back in there.

 

[cruiser88]

I don't see above freezing temps as reason enough for drastic warming measures to be taken. IF this is a cruiser motor, then perhaps the bypass hose isn't the problem. The o-ring inside the t-stat housing, on top of the t-stat; If it's torn, improperly installed, etc, it will allow nearly full bypass of the t-stat. This will cause over-cooling and the only fix is to get a properly installed o-ring back in there.

x2...

 

[sdbrassfield]

x3. The rig should heat right up w/in 2 miles. It is likely a deteriorated O-ring that is not seated in the thermostat housing.
Replace the thermostat and O-ring together.

 

[silicon_toad2000]

Thanks for that guys, I'll check the thermostat and o-ring.
Good point that blocking the bypass might harm the pump.

 

[lehiguy]

It's a Cruiser, staggering amounts of cast iron, four gallons of coolant, two gallons of oil; it takes time to bring it all up to temp.

 

[Elbert]

check the gaskets and o ring as others said... then take a longer trip to work. Its not good to start and run an engine when it never gets up to operating temp and then shut it off, espically on a routine basis. The engine needs to get to operating temp and stay there for a little bit before shutting it down.

 

[silicon_toad2000]

yeah, i know it aint the best thats why im looking for fixes and why I was wondering if anyone knew exactly why the bypass is there.
It should warm up well before i get to work.
10-15 minutes drive at 2000revs. It should wam up by halfway.

 

[Elbert]

I bet your o ring is gone..., you might consider replacing the thermostat when you check that.