Factory themrostat vs inline no question after week of cold

Layback1962 · **Posted:** Sat Feb 14, 2015 4:34 pm

Well, during the timing belt water pump change did the thermostat since it was stuck open.
Well determine that was the worst thing to do. Heat now sucks during the WI winter.
Putting back in the inline stat 195 degree in the now new hose.
( were did i put that old hose?) :banghead:

Hope it is Ok to have both work thermosats installed at the same time?
The inline stat brand does have a 1/16" hole drilled in it.

Thoughts anyone?

Layback

SBrooks · **Joined:** Sun Sep 17, 2006 7:30 pm **Posts:** 85

I have the in-line Stant installed in mine along with the original (ie, failed open) t-stat, and they work well together. Mine has heated up quickly this winter, and I experienced no overheating during the very hot NM summer last year.

Steve

flash7210 · **Posted:** Sat Feb 14, 2015 6:32 pm

I dont think that running a 195 deg inline with a functioning factory thermostat will cause any new problems.
The factory one will open at 172 deg and coolant will still not flow into the radiator untill the in line opens.

In my opinion, 195 deg in line will not help your engine warm up any faster. These engine are just slow to warm up in winter.
If you want faster cabin heat, plug in the block heater.

DOC4444 · **Posted:** Sat Feb 14, 2015 9:08 pm

I think almost everyone agrees that running these motors around 195 degrees improves efficiency. However, the in-line "add-on" can cause overheating in high ambient temp/high load ((towing, etc.) conditions. Personally, I have decided to hold off and wait for a modified version of the OEM multi-port thermostat.

(I have already replaced one head gasket. Not in the mood to do it again, or worse.

DOC

mass-hole · **Posted:** Sat Feb 14, 2015 9:08 pm

Someone correct me if I am wrong, the issue is that when the factory thermostat opens, I believe it blocks the return passage that let's the coolant back into the engine. In other words, when the factory tstat is closed(cold), the coolant is bypassed back into the engine. Once the coolant warms and the tstat opens it blocks the bypass and allows flow to the radiator.

thermorex · **Posted:** Sat Feb 14, 2015 11:10 pm

mass-hole wrote:

Someone correct me if I am wrong, the issue is that when the factory thermostat opens, I believe it blocks the return passage that let's the coolant back into the engine. In other words, when the factory tstat is closed(cold), the coolant is bypassed back into the engine. Once the coolant warms and the tstat opens it blocks the bypass and allows flow to the radiator.

From what I remember, you're correct.

LazyK · **Posted:** Wed Feb 18, 2015 10:26 pm

excellent description by Turbo-Diesel-Freak on the operation of the factory thermostat here
viewtopic.php?f=5&t=75791&start=240
and why you don't want to use the inline stats
about half way down the page

Layback1962 · **Posted:** Fri Feb 20, 2015 8:34 am

Factory themostat is new and working at 185 degrees.
Question is:
Can I run a working factory thermostat 185 degrees, and a inline hose stant 195 degree tstat at the same time?

This would help with the engine run better and getting better milage.

Thanks, layback

dirtmover · **Posted:** Fri Feb 20, 2015 11:43 am

Layback1962 wrote:

Factory themostat is new and working at 185 degrees.
Question is:
Can I run a working factory thermostat 185 degrees, and a inline hose stant 195 degree tstat at the same time?

This would help with the engine run better and getting better milage.

Thanks, layback

You're probably better off than with a failed, prematurely opening, factory 'stat but you still run the risk of having the factory bypass fully closed at the same time as the inline is fully closed. You will need to mitigate this risk with a suitably sized hole drilled in the inline.

The only failsafe solution is where the bypass and main diaphragms are mechanically coupled.

Factory themrostat vs inline no question after week of cold

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