Chevette LS1 Swap, overheating
Chevette LS1 Swap, overheating Hi there, I picked up a Chevette last week with an LS1 swap already done. The previous owner bought it as is a couple months ago and knew little about it. It had milky oil and got hot so head gaskets were deemed the issue. I trailered it home, changed oil (milk), retorqued the heads as a first step, added oil and drove it. It ran great, I beat on it pretty good for 5-10min and nothing bad happened. Yesterday I drove it to get gas and could tell it was getting hot by the crappy digital readout tool and before I could pull over it overheated. The radiator was completely cool, upper hose was luke warm at best, bottom hose to water pump was very hot. This is my first LS powered car so please point out my ignorance or mistakes so I can learn. From my analysis, the t-stat is not working and is causing head gasket issues due to overheating. Id like to mention that the radiator is shroudless, it has a 14" electric fan and the radiator hoses take some sharp bends. What do you guys think? Here is a pic of the car and engine bay to see the poor plumbing.
Couple things.
Where is that lower radiator hose going?
Are the lines coming off the front of the heads connected back to the radiator?
Have you tried yanking the thermostat to see if that fixes the problem?
Where is that lower radiator hose going?
Are the lines coming off the front of the heads connected back to the radiator?
Have you tried yanking the thermostat to see if that fixes the problem?
Lower radiator hose does a 270* turn and goes down and into the bottom corner of the radiator. Yes, the metal line that connects the corners of the heads comes straight out from under the intake and T's into the upper radiator hose. I have not yet, it puffed a little smoke when I started it back up and didn't wanna drive it till I was sure everything was right. I did however buy a new t-stat, head gaskets, head bolts etc. Would that be a good start or is there anything else I might be missing?
I removed the tstat completely, added water to radiator and let it run a few minutes and temp rose quickly. I added water as necessary and turned on the electric fan but it got up to 220 so I shut it off. Both radiator hoses didn't feel very warm and the radiator felt cool as well. My radiator is somewhat low, could that cause air to not to get burped out of the system?
TECH Resident
Joined: Apr 2014
Posts: 985
Likes: 12
Have you put a pressure tester on the coolant system to see if it will hold pressure?
Or you can do a block test and see if you are getting combustion gasses in coolant
system.
You can google coolant pressure test or block check, should get you headed somewhere.
Or you can do a block test and see if you are getting combustion gasses in coolant
system.
You can google coolant pressure test or block check, should get you headed somewhere.
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I have not pressurized the system yet which is a good idea. I do know at some point though it will mix coolant in the oil, no oil in the coolant though. I plan on doing head gaskets in the next two days, I just find it weird the radiator wasn't even hot yet my car was on the verge of overheating. That's why I want to make sure there's nothing obviously wrong with the cooling system causing the head gaskets to go out so I don't blow the new ones.
edit: I also have no surge tank, just overflow
edit: I also have no surge tank, just overflow
Last edited by elliss12; Jun 21, 2016 at 07:36 AM.
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TECH Resident
Joined: Feb 2014
Posts: 954
Likes: 9
From: Encinitas CA
I was thinking the water pump might be turning the wrong direction, too.
Also, I will hope for the best for you, but I would think milky oil won't be addressed simply by re-torquing the heads. I'd expect you to have to pull them, mill them flat and then re-install.
Good luck,
Doug
Also, I will hope for the best for you, but I would think milky oil won't be addressed simply by re-torquing the heads. I'd expect you to have to pull them, mill them flat and then re-install.
Good luck,
Doug
Aston Tibs- I think it is but let me know if this pic helps. Whether it works though is beyond me
DW SD- Youre right, I figured I'd give it a shot though considering its free. New head gaskets and bolts should be here today though so I can address that assuming heads are flat and crack free.
My radiator cap is not the highest point, would this cause a large air pocket and lack of coolant to flow? Im thinking yes. If so, I need to add a surge tank or find a way to bleed all the air out from the highest point (coolant outlet on water pump). Any ideas?
DW SD- Youre right, I figured I'd give it a shot though considering its free. New head gaskets and bolts should be here today though so I can address that assuming heads are flat and crack free.
My radiator cap is not the highest point, would this cause a large air pocket and lack of coolant to flow? Im thinking yes. If so, I need to add a surge tank or find a way to bleed all the air out from the highest point (coolant outlet on water pump). Any ideas?
My steam port is the black hose coming out from under the intake manifold in that previous pic. It just T's into the upper radiator hose. In theory, yes it should releave steam/air from the heads in the cooling system. But if the radiator is not my highest point, I feel like the air is just being trapped in the engine. In my thinking anyways
TECH Resident
Joined: Feb 2014
Posts: 954
Likes: 9
From: Encinitas CA
Yes, you'll need to bleed out the air, especially if it surrounds the thermostat. If it doesn't open, it could cause an overheating condition.
I'd put an inline filler (with cap) on the top radiator hose. The filler should be at the highest point in the cooling system. You could probably buy a reservoir from a junk yard that would serve this purpose.
OR for a very temporary solution:
You could put an inline filler or T with a cap in the heater core hoses, but you'll need to make the valve is open to the heater core, so as to allow the air to escape as you top off the system.
Next, the steam vent line will capture air at the high point of the hose. The vent should also attach to a point above the steam outlets so air can escape.
Finally, I believe:
1. either your thermostat isn't opening due to being surrounded by air.
2. your water pump is turning backwards.
3. To use reliably you'll likely need to resolve the blown head gaskets.
Doug
I'd put an inline filler (with cap) on the top radiator hose. The filler should be at the highest point in the cooling system. You could probably buy a reservoir from a junk yard that would serve this purpose.
OR for a very temporary solution:
You could put an inline filler or T with a cap in the heater core hoses, but you'll need to make the valve is open to the heater core, so as to allow the air to escape as you top off the system.
Next, the steam vent line will capture air at the high point of the hose. The vent should also attach to a point above the steam outlets so air can escape.
Finally, I believe:
1. either your thermostat isn't opening due to being surrounded by air.
2. your water pump is turning backwards.
3. To use reliably you'll likely need to resolve the blown head gaskets.
Doug
In that second pic, it looks like the belt is running underneath the water pump so you should be good. I think it has to do with the radiator cap not being the high point in the system. You are air bound.
I think you both are right with air not getting bled. I think what ill do temporarily is plumb the steam port into the top of my water pump and move the inline "T" filler that it was plumbed into almost directly off the outlet of the water pump so it sits high. Although its a small fitting, I should be able to use it as a fill/bleed port if I go slow. It sucks that this engine sits up so high, its making this simple task a little tough. It also sucks that they didn't just get a radiator with ports on the same side. The water pump pulley is almost rubbing the upper hose. Thanks for the input so far guys!
So, get one. You also don't know if the previous owner plugged up the radiator w/ a gasket repair product or if the radiator & fan(s) are correctly sized. If the air bleeding; etc. doesn't work (probably won't), get a new radiator w/ ports in best location & a radiator w/ @ least 1-1/4" tubes & fan(s) w/ @ least 1300-1400 CFM total capacity or add a voltage multiplier to your fan(s) & run @ 16-17 volts. The car has puller fans, of which is a cfm reduction to start with.
Most affordable dual pass radiators have 1" tubes & 2" cores despite being 3" thick. An 1 1/4" tubed radiator will have an approx. 2.7" core & would only add around $100 more to the cost (still relatively a cheap radiator). The mfg. site will show the core specs. So, you can confirm them before buying from one of their vendors. Good-luck
Thanks for the suggestions, and yes I would love to get a new one that is on the correct side. It just stinks because this is a nice newish griffin radiator but I don't like the plumbing so maybe i'll just have to bite the bullet. I'll try getting the air bled first though and new head gaskets. Its still strange that the coolant in the radiator is not hot with thermostat removed and the car indicating it is 220* and climbing. Probably the mixture between air pockets and head gaskets sealing since the temp sensor is in the head. I'll report back any odd findings when I pull the heads tonight!
Jack up the front of the car to get the radiator inlet as high as possible. Than pull one of the steam vents at the front of the motor as you fill the radiator. Keep going until water comes out of the vent, then put the vent back in.
That will get all the air out. I pop one of the vents everytime I fill or drain the system.
You also know pulling the thermostat will open the water pump bypass. This makes the water just circulate inside the pump and not go through the block. Never run an LS without a thermostat.
That will get all the air out. I pop one of the vents everytime I fill or drain the system.
You also know pulling the thermostat will open the water pump bypass. This makes the water just circulate inside the pump and not go through the block. Never run an LS without a thermostat.
Pop N Wood- That method might just work, its only lower by an inch or two. I'll try that once I put it back together. I did not know that at all, that would explain why only the engine was getting warm. Thanks for all the help!
Update: Got heads pulled, i'll mention so maybe you guys can make sense out of whats going on here. The passenger head is ported while the other head is untouched. Also #7 cylinder has a new std. piston and cylinder has a long gouge. I dont see any cracks in the head or block yet. Using a straight edge they seem flat so far. I will verify with feeler gauges though. Any of you guys see anything obvious?
The new guy, std. bore
left bank
8&6
4&2
Right bank head
Left bank head
Update: Got heads pulled, i'll mention so maybe you guys can make sense out of whats going on here. The passenger head is ported while the other head is untouched. Also #7 cylinder has a new std. piston and cylinder has a long gouge. I dont see any cracks in the head or block yet. Using a straight edge they seem flat so far. I will verify with feeler gauges though. Any of you guys see anything obvious?
The new guy, std. bore
left bank
8&6
4&2
Right bank head
Left bank head
Last edited by elliss12; Jun 21, 2016 at 08:19 PM.