Block coolant bypass hole plugged!
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Joined: Dec 2007
Posts: 79
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From: Redmond WA
Block coolant bypass hole plugged!
Hello folks, that's me again.
I still doing my cooling system overhaul, now I realized that the small hole under the bottom passenger side water pump bolt (coolant bypass) is plugged with white cement or something similar.
I'm wondering what will be the implications of that since the system has no way to relieve pressure when the thermostat is closed.
Before I cracked it open it had a loop in the heater hose from the intake mainfold to the water pump, probably releasing the extra pressure.
I'm not sure how deep the cement is, if that channel is straight I guess I can drill it, if not I might need to go for more radical measures like drilling the thermostat, which I dont like since it will spoil my optimal running temperature.
Please advise!
Fábio
I still doing my cooling system overhaul, now I realized that the small hole under the bottom passenger side water pump bolt (coolant bypass) is plugged with white cement or something similar.
I'm wondering what will be the implications of that since the system has no way to relieve pressure when the thermostat is closed.
Before I cracked it open it had a loop in the heater hose from the intake mainfold to the water pump, probably releasing the extra pressure.
I'm not sure how deep the cement is, if that channel is straight I guess I can drill it, if not I might need to go for more radical measures like drilling the thermostat, which I dont like since it will spoil my optimal running temperature.
Please advise!
Fábio
Pro
Joined: Jun 2005
Posts: 583
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From: USA
I would drill small holes in the thermostat. I actually prefer this, compared to allowing coolant to bypass the radiator when the motor is hot. The objective is to maximize coolant going through the radiator. I now routinely plug all my SBC bypass holes by using an alum pipe thread plug in the corresponding hole in the water pump, also, not using a bypass hose in my BBC.
the trade-off is marginally longer warmup when the motor is cold (drilled holes in T-stat), or whether to get max coolant through the radiator when the motor is hot (factory bypass). My guess is C3's need all the cooling they can get.
But Hawaii isn't Washington state. Heaters are disconnected out here.
I drill a couple (2-3) 1/8" holes. This has been in the magazines. I don't consider this to be "radical". Radical is "not running a T-stat", or an orifice plate instead of a T-stat.
the trade-off is marginally longer warmup when the motor is cold (drilled holes in T-stat), or whether to get max coolant through the radiator when the motor is hot (factory bypass). My guess is C3's need all the cooling they can get.
But Hawaii isn't Washington state. Heaters are disconnected out here.
I drill a couple (2-3) 1/8" holes. This has been in the magazines. I don't consider this to be "radical". Radical is "not running a T-stat", or an orifice plate instead of a T-stat.
Pro
Joined: May 2005
Posts: 592
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From: Shreveport Louisiana LSU
I'm not aware of a water bypass hole. Heater hose looped from the intake to the water pump is just a heater by-pass (bad core or something) Generally, white stuff blocking an exposed hole is put in by an insect. We call them dirt dobbers down here. Are you talking about the threaded hole that goes into the fuel pump push rod area?
Thread Starter
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Joined: Dec 2007
Posts: 79
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From: Redmond WA
I'm talking about this hole:
http://iotech.no/corvette/technical/...te_cooling.htm
look the picture at the bottom.
Rpol: Thanks for your answers
I just removed all my AC stuff, we don't need it here, I replaced tha radiator with an aluminum one, and the water pump with the best stuff edelbrock has. Electric fan, air dam, everything is looking perfect even for Florida, so I think I don't really need the extra cooling.
What I might need though is lower warmup time and I read a few stuff about running temperature and how crucial it is, so I'm convinced to leave the t-stat alone.
http://iotech.no/corvette/technical/...te_cooling.htm
look the picture at the bottom.
Rpol: Thanks for your answers
I just removed all my AC stuff, we don't need it here, I replaced tha radiator with an aluminum one, and the water pump with the best stuff edelbrock has. Electric fan, air dam, everything is looking perfect even for Florida, so I think I don't really need the extra cooling.What I might need though is lower warmup time and I read a few stuff about running temperature and how crucial it is, so I'm convinced to leave the t-stat alone.
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Joined: Dec 2007
Posts: 79
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From: Redmond WA
So guys? No one to yell at me saying it's all wrong and I should drill holes into some crazy place like the timming chain cover, or suggest some good stuff acid to melt the cement, or even to say that I shouldn't have replaced the stock pump?
Come on! This community is better than that
let's get into a fired up discussion over it! 
Fábio.
Come on! This community is better than that
let's get into a fired up discussion over it! Fábio.
Thread Starter
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Joined: Dec 2007
Posts: 79
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From: Redmond WA
Ok I'm at the garage now, removed the pump and the stuff is not white, its black and feels like powder, easy to remove and should be of metalic base becase its sticking to my magnetic screwdriver.
The bad news is that it seems to have a bend and I have no idea to which side!
Do I have to open the engine stamps to access it?
Does someone have an xray diagram of the chevy 350?
Please help!
The bad news is that it seems to have a bend and I have no idea to which side!
Do I have to open the engine stamps to access it?
Does someone have an xray diagram of the chevy 350?
Please help!
Thread Starter
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Joined: Dec 2007
Posts: 79
Likes: 1
From: Redmond WA
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Thread Starter
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Joined: Dec 2007
Posts: 79
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From: Redmond WA
Ok Guys, I got it. It bends towards the passenger head, and black stuff seems to be the same black powder we get from the exaust.
Someone please explain how this got there! Do you think my head seal is busted and that stuff is getting to the water lines?
I know that that bypass is designed to keep the area around the spark plugs cooled during warm up... But how this stuff got there?
Please don't tell me I have to remove the cylinder head to figure it out/clean it!
Fábio.
Someone please explain how this got there! Do you think my head seal is busted and that stuff is getting to the water lines?
I know that that bypass is designed to keep the area around the spark plugs cooled during warm up... But how this stuff got there?
Please don't tell me I have to remove the cylinder head to figure it out/clean it!
Fábio.
Racer
Joined: Sep 2006
Posts: 484
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From: McComb Ms.
at some point somene might have used a radiator sealant to stop a leak as you mentioned radiator change.said is was metallic so it's not pepper.maybe someone knows something i don't so don't drive it for a day or so until you hear from forum members with experience in this matter
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Joined: Dec 2007
Posts: 79
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From: Redmond WA
I had the theory they only plugged the outlet with the white stuff a long ago, creating this dead end tunnel from the head. As the time passed a lot of lose rust deposited in the dead end tunnel and after drilling it I had to clean up all the way to the cylinder head.
But your theory on the sealant makes a lot of sense too, it would definetelly get deposited on this dead end tunnel.
The car is far from working so let's see what the wise guys bring on the next few days.
Fábio.
But your theory on the sealant makes a lot of sense too, it would definetelly get deposited on this dead end tunnel.
The car is far from working so let's see what the wise guys bring on the next few days.
Fábio.
Last edited by FabioSan; Mar 5, 2008 at 01:22 PM.
Burning Brakes
Joined: Sep 2005
Posts: 993
Likes: 3
From: Iowa
We plug the bypass on all of the engines we build, either with a plug like mentioned above or with a water pump that does not have a bypass (like the Stewart pumps). This combined with several hole in the t-stat allow the cooling system to build pressure in the radiator increasing its efficiency. For our guys that run these engines in the cold Midwest winters we recommend switching out the t stat with one that has very small holes drilled to allow for warm up. As long as this is done we have not experienced any problems and reap the benefits of the additional cooling a 650+hp engine needs at wot when compared to cruising. Just our .02.
