overheating problem
- Thread starter oino
- Start date
TriodeLuvr
Member
That reminds me of a guy I knew years ago who put a performance cam in his ~ '72 Challenger. The car had been running fine, but it started overheating after that. I guess it was the increased duration that did it; he solved the problem by installing a larger radiator. Luckily, he had only changed one thing, so the culprit was a little easier to diagnose.
Jack
Manifold reinstalled. No more oil or vacuum leak. Tested Vac. with vac. gauge 16.
Still overheating. I looked into the Bypass. As far as I can tell that is for vortec blocks/heads that change to a carb manifold. Them blocks don't have a bypass built in.
Older blocks have the bypass built the lower passenger side of the waterpump/block.
Looks like its head pulling time this weekend.
Still overheating. I looked into the Bypass. As far as I can tell that is for vortec blocks/heads that change to a carb manifold. Them blocks don't have a bypass built in.
Older blocks have the bypass built the lower passenger side of the waterpump/block.
Looks like its head pulling time this weekend.
Ok, Can any of you comfirm this.
I found on the web about vortec heads missing a water hole thats on older chevy heads. I think the bypass is my problem.
I can't save the image from camaroperformers to post it.
Here is the text under the image.
"Laying the head gasket of the TPI motor onto the Vortec head shows a water routing difference. Notice the head gasket for the stock small-block head has an opening for routing bypass water through the head. Vortec heads are not so equipped."
They also have an image showing the bypass in the block and where is would connect with the head if I had that hole.
I found on the web about vortec heads missing a water hole thats on older chevy heads. I think the bypass is my problem.
I can't save the image from camaroperformers to post it.
Here is the text under the image.
"Laying the head gasket of the TPI motor onto the Vortec head shows a water routing difference. Notice the head gasket for the stock small-block head has an opening for routing bypass water through the head. Vortec heads are not so equipped."
They also have an image showing the bypass in the block and where is would connect with the head if I had that hole.
Screaming Metal
Active Member
SPECIAL NOTE: This intake manifold is primarily intended for use with Vortec-style heads on pre-Vortec blocks. Standard engine blocks
route the thermostat bypass water from the block directly to the water pump through the passenger side water pump mounting flange. If the
manifold is used on a 1996 or later Vortec engine that does not have the in-block bypass passage, you must route a thermostat bypass hose
from the water bypass port on the front of the intake manifold to the 5/8” hose nipple on the passenger side of the Vortec water pump. Use
a 3/8” NPT (pipe thread) to 5/8” hose nipple fitting, and a 7” length of 5/8” hose to accomplish this. If your engine block has the thermostat
bypass passage, use the 3/8” NPT plug supplied in the kit to plug the bypass port in the front of the intake manfold.
Is this what your talking about????
route the thermostat bypass water from the block directly to the water pump through the passenger side water pump mounting flange. If the
manifold is used on a 1996 or later Vortec engine that does not have the in-block bypass passage, you must route a thermostat bypass hose
from the water bypass port on the front of the intake manifold to the 5/8” hose nipple on the passenger side of the Vortec water pump. Use
a 3/8” NPT (pipe thread) to 5/8” hose nipple fitting, and a 7” length of 5/8” hose to accomplish this. If your engine block has the thermostat
bypass passage, use the 3/8” NPT plug supplied in the kit to plug the bypass port in the front of the intake manfold.
Is this what your talking about????
That is what edelbrock says. I think is wrong.
I just found this on thirdgen.
"
GM instructions:
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 the 3/8" boss on intake manifold to the water pump."
Yep, I hope so.
I have extra hose, and I'll get some pipe fittings from my friends shop later.
I'll give that a try after work. If this works it's a lot cheaper then removing the heads.
You know the manifold I got has that hole in from of it. I wondered why they put a hole there. But it came with a plug so I pluged it.
I'm thinking that the reason some people don't need the bypass, is that maybe the aftermarket vortec heads have the bypass hole in them.
Last edited:
Screaming Metal
Active Member
Where I'm looking all over the net its saying its a external bypass problem. They ought to tell these people when they buy those heads that they will have to go this route....
It would be very easy for someone to melt down a mill because they didn't explain themselves....
It should be easy, a couple of nipples, some hose, some sealer and a couple of hose clamps, and a little time.
Screaming Metal
Active Member
Damn, just mashed my finger looking at the heads he's using. Yea, if his waterpump doesn't have the bypass, the coolant deadheads in his intake. Thats some tricky mess, I imagine a few folks probably burnt things up.
Hey, oino, what waterpump are your running?
Hey, oino, what waterpump are your running?
I'm using a sbc stock water pump.
It has the bypass. But its stop at the bottom of the head. Because the hole that lets it flow up to the intake is blocked off at the head.
Ok, Wasted my lunch break and got the bypass installed. It's working some what. I used 5/16th hose that I had. The temps on both gauges are going up.
The efi gauge is still a little slower. About 20 degrees behind. So I think I need a larger bypass hose. I'm going to 3/8, But maybe it needs to be 5/8.
The hole in the head only looks to be about 3/8.
http://www.camaroperformers.com/cam...7.html?&_suid=1378303066704012557517971712773
That site has the image showing the bypass in the old chevy block and a image of how the bypass isn't in the head.
That site has the image showing the bypass in the old chevy block and a image of how the bypass isn't in the head.
Screaming Metal
Active Member
GM instructions:
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 the 3/8" boss on intake manifold to the water pump."
Yes, I'd run 5/8's....to be on the safe side....
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 the 3/8" boss on intake manifold to the water pump."
Yes, I'd run 5/8's....to be on the safe side....
I'll get some 5/8 hose tomorrow.
Spoke to soon about oil leak being gone. All 4 sides of the engine are leaking oil. The oil is at the bottom corners of the heads. It can't be coming from the manifold. I don't see any oil coming down from the manifold. I don't see any from the valve covers. So I'm not sure.
Vacuum is still fine.
Spoke to soon about oil leak being gone. All 4 sides of the engine are leaking oil. The oil is at the bottom corners of the heads. It can't be coming from the manifold. I don't see any oil coming down from the manifold. I don't see any from the valve covers. So I'm not sure.
Vacuum is still fine.
Mike
Well-Known Member
One area that can give you oil leak fits are the strut areas leading from the deck up to the end seal areas.
A bead of silicone on both sides of the head gasket (only in the indicated areas) can seal those leaks right up. The area where the side gaskets meet the end seals can always benefit from a bit more silicone, too.
A bead of silicone on both sides of the head gasket (only in the indicated areas) can seal those leaks right up. The area where the side gaskets meet the end seals can always benefit from a bit more silicone, too.
So your saying I need to remove the manifold again.
I don't see any oil running down from there with I look into the crack between the head and block. I don't start seeing oil until about an inch away from the bottom of the block.
I'll see if I can get a good pic of it.
2old2fast
Active Member
Are you sure it's oil ? When I put the new Brodix heads on my small block I noticed what I initially thought was oil , after some detective work it was found to be antifreeze , a bottle of bars leak put an end to that . I'm not saying it couldn't leak where Mike has shown , just that in 1/2 century & many small blocks , I've never seen or heard of it. More likely , if it is oil, that's it's running down from above .
dave
dave
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