Coolant bypass hose and hole in thermostat [Archive] - Chevy Nova Forum

: Coolant bypass hose and hole in thermostat


siderman
31st-May-2010, 11:14 PM
Like most I've had some cooling issues. I run a coolant bypass hose from the Water pump to the intake. With the cap off of the radiator I can see coolant flow, but it flows alot more when I rev it up a little. My dad suggested taking out the hose and plugging the hole to get more flow through the radiator. I don't have a heater either.

I google this a little and got several views. Some say you need it, some don't. Some did mention drilling holes in the thermostat if your not going to use one. Whats your views on this?
thanks

levisnteeshirt
31st-May-2010, 11:18 PM
i wasn't going to run a heater core bypass line ,, i'd look at the moroso flow restrictors to keep some coolant moving through the engine all the time ,, instead of a thermostat

Seattle_Mike
31st-May-2010, 11:39 PM
Unless you are running a high compression, boosted, type engine, you shouldn't be having cooling issues and should have no reason to not use the bypass hose, nor should you have to drill the thermostat. How is your cooling system setup? What type radiator, are you running a shroud, a belt driven clutch fan, electric fan, what thermostat? It sounds like you are running a belt driven pump.

Plowman
1st-June-2010, 07:59 AM
Drill the Thermostat.

siderman
1st-June-2010, 10:08 AM
Why drill the thermostat? I read about pressure building under it not allowing it to open?

Large Summit Aluminum radiator

160 degree mr gasket T-Stat

Flexalite fan setup with the built in shroud that covers basically the whole radiator. About 3000 CFM if I remember.

ZZ502 Crate with Edelbrock EFI

Plowman
1st-June-2010, 12:42 PM
At the headgasket is the hotest spot in the coolant system. Some times coolant BOILS just a bit. BOILS = is to vaporize a liquid by applying heat. That air gets behind the thermostat and causes air pockets. Drilling the thermostat lets traped air out. Some new thermostats come with a hole and caged ball in them.

Shane65
1st-June-2010, 01:08 PM
I always drill a hole in the thremostat(two smaller ones if need be). As Mike says, it shouldn't be needed but it does make for a smoother temperature rise in the engine with it. First time coolant installation is better because air pockets are minmized. Alittle coolant can flow if the thermostat fails. It may not be enough but at least some is getting through.

jer66nova
1st-June-2010, 03:02 PM
Why drill the thermostat? I read about pressure building under it not allowing it to open?

Large Summit Aluminum radiator

160 degree mr gasket T-Stat

Flexalite fan setup with the built in shroud that covers basically the whole radiator. About 3000 CFM if I remember.

ZZ502 Crate with Edelbrock EFI

Try changing to a real thermostat those Mr gasket ones are crap get a Stant one or napa also check your radiator pressure cap 16-18 psi moroso makes race caps 25psi takes longer for water to boil under presure the thermostat opens by the heat not pressure under it the spring closes it as it cools check it in a pot on the stove

Plowman
1st-June-2010, 04:00 PM
If there is a air pocket under the thermostat,it will not opean correct temp[much hotter air to opean the same thermostat]. Liquid coolant opens the thermostat at correct temp.

Tubbed63
1st-June-2010, 04:15 PM
Try changing to a real thermostat those Mr gasket ones are crap get a Stant one or napa also check your radiator pressure cap 16-18 psi moroso makes race caps 25psi takes longer for water to boil under presure the thermostat opens by the heat not pressure under it the spring closes it as it cools check it in a pot on the stove



Actually the Mr Gasket high flow thermostat is a robert shaw thermostat so no they are actually very high quality thermostats.

siderman
1st-June-2010, 04:16 PM
someone got a pic of a drilled thermostat?

I bought a new waterneck today with a vaccuum port and an air bleed valve. I think I'll put it in a make sure that no air pockets are in there. It's cheap insurance. I've had alot of problems with air pockets in my cavalier. I'll drill the thermostat with it out.

Plowman
1st-June-2010, 04:56 PM
The air pockets are under the thermostat.

Seattle_Mike
1st-June-2010, 05:57 PM
Raise the front end of your car when you fill the cooling system...that usually eliminates air bubbles.

onecarnut
1st-June-2010, 06:46 PM
Drill the Thermostat.

I always drill two very small holes in the thermostat.

Reason -

BEFORE drilling, my temp gauge would spike to a high reading just before the thermostat opened.

AFTER drilling, my temp gauge made a normal climb until it reached the opening value of the "stat".

I think the small holes lets a little of the hot water and air escape from the engine before the thermostat opens.

siderman
4th-June-2010, 04:13 AM
Installed the new waterneck with the air bleed valve today. Checked the thermostat on the stove and it opened fine. It has a place for air to bleed out already made in, so there was no reason to drill. Only problem I could see is that the passageway for water flow really looks small to me. If problems continue in the future, I may go a different route here and see if a little more flow may help my problem.

Refilled coolant and ran car to temperature with the frontend raised. Pushed on the air bleed and it was all water, which is good. Will try a good road test tomorrow. Also need to tune the EFI. I noticed on the air/fuel meters that there were some spots in the RPM range that tended to lean under flat throttle just driving. If I got on it a little more, it went immediately to the rich side.

Plowman
4th-June-2010, 10:45 AM
So when you are riding down the road and AIR get's under the thermostat,you will get out of the car and push on the air bleed[why not drill a hole in the thermostat,that will automaticly bleeds the AIR,as you drive]?

siderman
4th-June-2010, 12:03 PM
So when you are riding down the road and AIR get's under the thermostat,you will get out of the car and push on the air bleed[why not drill a hole in the thermostat,that will automaticly bleeds the AIR,as you drive]?

no, the air bleed is there to make sure all the air is out once in a while. I was going to drill the thermostat, but it already has an air bleed cast into the top. Being able to push the button also is a quick reference that your T-stat is open.

I have an 87 cavalier that I drive to work, and they have a real problem with air getting in the heads and having a problem. There is an 1/8" NPT fitting cast into the water neck on these that you are supposed to bleed the air out with. I never thought of raising the front to get the air out, but it caused me alot of headaches till I figured that out. Looking at the tech manual tells you to do that or you could harm a head.

laser-red-nova
4th-June-2010, 08:18 PM
Just something I have allways done and never had any "bubble" problems. Take the thermostate housing off and fill the block from there up to the top. Then put the themostat in and fill the radiator the rest of the way up. Just a little more. No Air bubbles. Try it you'll like it.

Plowman
5th-June-2010, 12:13 PM
Stewart high-performance water pumps require that three 3/16-inch holes are drilled into the themostat for bypass. Stewart also has available a high-performance themostat which is pre-drilled and ready for installation.

siderman
5th-June-2010, 07:15 PM
mine is an 8850 Edelbrock Victor.