Beating a dead horse - Vortec coolant bypass

[Portland68]

Can’t believe I haven’t been able to find a decent solution between this website and the google machine, but here we are again.

I’ve got my bypass in the correct location (pardon the poor routing, we were in a pinch) and will be trying out some pre bent hose, but I’m curious if I can run the hose directly to the radiator spot circled in the picture or if I should just drill 2 3/16 holes in the thermostat.

I haven’t been able to find a good solution and the motor got way hot when I first fired it up, probably due to trapped air at the t stat and my temporary hose. What solutions seem to work for you all?

[D.PASSMORE]

Good question, I was searching the other day for some fittings or pre-made hose.

[truckster]

I went to the auto parts store and found a piece of pre-bent coolant hose, but I've got my coolant coming out where you have your temp sensor.

[geezer#99]

That short bypass is hard to hook up.
Might be easier to use a spacer like this with a more accessible port and a longer hose.

https://www.jegs.com/i/Meziere/680/WN0028B/10002/-1

[FirstOwner69]

This is what I did on my Chevrolet Performance Vortec crate engine. Note the spacer under the thermostat housing for clearance. Seems to work fine.

[D.PASSMORE]

Originally Posted by FirstOwner69

This is what I did on my Chevrolet Performance Vortec crate engine. Note the spacer under the thermostat housing for clearance. Seems to work fine.

Nice - can you divulge your sources?

[randy500]

There is no good reason to not just drill the thermostat on every single new engine install or anytime the block is low on coolant from changing parts.
The hole will ensure the block fills completely with coolant.
There is absolutely no down side to drilling the thermostat.

I Usually fill the cooling system with the heater core hose off the manifold fitting until i see coolant flow out of it. I still do this with a drilled thermostat but its not really necesarry.

[KQQL IT]

https://www.jegs.com/i/Meziere/680/WN0028S/10002/-1

?

[FirstOwner69]

Originally Posted by D.PASSMORE

Nice - can you divulge your sources?

I believe the fittings were from an eBay source and not sure on the hose. I recall posting the info in another thread (possibly a PM) about 6 or 7 years ago. I spent about 2 hours looking for that thread but no luck. I'm pretty sure I have the receipts, but it'll be about a month before I can check. Big help, huh?

[Sheepdip]

Been drilling thermostats since the 70's....never a problem. I even purchased a thermostat once that already had a vent hole in it from the mfg but have not seen one since.

[toolboxchev]

I have seen the rear of the intake manifold drilled and tapped with fitting coming from both heads. This would be from the rear and they route hoses up to somewhere???

If anyone has pics please post them up!

[KQQL IT]

Kit with the similar spacer I posted above.
I dont know why you couldn't turn it around and use one of the fittings as a bypass.

https://www.jegs.com/i/JEGS/555/51100/10002/-1

[Jrainman]

When I transplanted a L31 vortec in my c10 , here is just some information I found , GM issued instructions state :The Ramjet 350 engine includes a standard rotation water pump this is a cast iron,LONG Leg water pump :the same pump installed on GM performance parts ZZ4 crate engine . Any small block engine regardless of year,that uses Vortec Heads,will require an external coolant bypass line from the intake manifold to the 5/8'' hose nipple on the water pump (passenger's side) suggested routing is from 3/8" boss on intake mainifold to water pump.

And here is some information I found and is vital in cooling a vortec engine: The serpentine belt that runs all accessories off one belt uses REVERSE Rotation water pump,because of the way the belt is wound around everything they use the back side of the serpentine belt wrapped in the opposite direction around the pump, Ford v8 serpentine belt is the same way,pump has to be a reverse rotation compared to earlier v- belt system pumps ..

this is the information I used in my L31 transplant and my truck runs 181 -186 degree 99 percent of the time on very hot days 95 degree and up I will have up to 191 degree spikes on my engine coolant temp when stopped in traffic on very hot days.

one more thing to remember:
Engine driven cooling fans also have to match the pump,reverse rotation Pumps have to have reverse Pitch fans because they are spinning in the opposite direction, make sure the fan is also correct for your application or it will impact cooling also, using the wrong fan will try to push air foward through the radiator ,fighting road airflow and also leading to highway overheating .

[Sheepdip]

Originally Posted by toolboxchev

I have seen the rear of the intake manifold drilled and tapped with fitting coming from both heads. This would be from the rear and they route hoses up to somewhere???

If anyone has pics please post them up!

That's an old circle track/sprint car trick. Some after market manifolds come pre-drilled and tapped for that purpose.

[toolboxchev]

Originally Posted by KQQL IT

Kit with the similar spacer I posted above.
I dont know why you couldn't turn it around and use one of the fittings as a bypass.

https://www.jegs.com/i/JEGS/555/51100/10002/-1

So this is the kit you would route from the back ports on the intake I would guess. Does anyone know if it would be any more effective?

Looking at the dollars for a build.

[KQQL IT]

You could just buy the spacer. Plug one side and use the other side as the bypass?

[randy500]

Or you could just drill the thermostat.

[tdangle]

This is what I did. The bypass hose just touches the bottom of the rad hose.

[HO455]

I picked one of these 67 and earlier factory spacers for 5 bucks at the wrecking yard for my truck. One more piece of evidence proving the old lady right that I am a cheap ba$$terd.

[kidatheart]

Originally Posted by randy500

Or you could just drill the thermostat.

Randy500: could you post a picture of a drilled thermostat housing? This is new to me-I like to learn all I can when I can.

edit: Never mind-I reread your post and saw that it said drill the thermostat, not housing. I know about that. But thanks anyhow. Doug

[KyFarm]

I am slowly installing a chevy crate motor with vortec heads in my truck and hopefully soon will be to the point of routing cooling hoses,

I would appreciate seeing a picture of a drilled thermostat

[Jrainman]

Originally Posted by kidatheart

Randy500: could you post a picture of a drilled thermostat housing? This is new to me-I like to learn all I can when I can.

edit: Never mind-I reread your post and saw that it said drill the thermostat, not housing. I know about that. But thanks anyhow. Doug

There are a few t/stat manufactures out there that sell T/stats that already have bypass holes drilled in them , you can find these t/stats at places like Speedway and yes with pictures....

[randy500]

Not my picture. I actually use a punch but a drill works fine. Some people drill more than one hole.
Many vehicles have a factory hole.

[jnd42697]

So after reading the posts about cooling bypass lines, you say its a simple as drilling a 3/16" hole just like the one in the picture? No cooling issues with that? Not doubting just asking. It makes sense, the bypass lines that the thermostat out of the equation.

[bigmac73]

this is funny there is another thread just like this on about 6 or 7 above,just drill a hole in the thermostat that i did also take a look at the other thread on this same subject i posted a link on there and as others