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I've had a bear of a time twice in my LS swap experience getting the air out of the system. The easiest way I have found is to disconnect the upper radiator hose and fill the engine through the hose then connect to the radiator and top off. I almost guarantee this is your issue, LS engines are, indeed, very easy to keep cool.
I've had a bear of a time twice in my LS swap experience getting the air out of the system. The easiest way I have found is to disconnect the upper radiator hose and fill the engine through the hose then connect to the radiator and top off. I almost guarantee this is your issue, LS engines are, indeed, very easy to keep cool.
The problem with these motors is that the steam ports are higher than the ports that feed water into the water pump (also a problem with the 90's LT1 motors). The upper radiator hose is fed by the water pump. So, simply removing the upper hose at the radiator may not get out all of the air especially since your rear steam ports are blocked (GM started blocking the rear ports on the later LS engines so it is not a problem). With the radiator full and the engine cold, simply loosen the bolts on the rear steam port block offs until a seady stream of coolant comes out, then tighten. You can do the same thing with the front steam port connections or remove the hose attached to the steam port crossover going to the radiator. The steam port fittings are sealed with O-rings so doing this will not "hurt" any gaskets.
The problem with these motors is that the steam ports are higher than the ports that feed water into the water pump (also a problem with the 90's LT1 motors). The upper radiator hose is fed by the water pump. So, simply removing the upper hose at the radiator may not get out all of the air especially since your rear steam ports are blocked (GM started blocking the rear ports on the later LS engines so it is not a problem). With the radiator full and the engine cold, simply loosen the bolts on the rear steam port block offs until a seady stream of coolant comes out, then tighten. You can do the same thing with the front steam port connections or remove the hose attached to the steam port crossover going to the radiator. The steam port fittings are sealed with O-rings so doing this will not "hurt" any gaskets.
Very good info..But shouldn't the engine be a little warm so the coolant can have pressure to come out??? Also should the engine be running while performing this operation??
Very good info..But shouldn't the engine be a little warm so the coolant can have pressure to come out??? Also should the engine be running while performing this operation??
The engne does not need to be running and it does not need to be warm (you could probably have it running and warm, but the rear ports may not be easy to get to so a motor that is running and hot will just make the job that much harder). You are simply allowing the coolant to push out all of the air using gravity. It will not be like bleeding brakes. The radiator just needs to be filled higher than the steam ports so that the air will be forced out when you loosen the steam port fittings. For a conventional motor like a BBO, beedling is not nesessary becuase the thermostat is the highest point. Motors with a thermostat at the highest piont can still get air pockets causing heating issues, but usually only result in false readings showing that the motor is hot when it isn't because the thermostat has not opened yet. With the LS, the highest area of the head (especially at the back) can get air trapped in it that has no way to get out without bleeding it. On my LS1, I made a system with Earl's steam vent fittings, 3 AN fittings, 3/16 stainless line, and a 5 port distribution block so that the steam vents connect under the intake and flow into the top of the water pump at the upper radiator hose exit. Even with the 4 ports connected together, I still bleed the system whenever I refill the cooling system any time I have it drained. The front driver side steam port has a swivel 3 AN port that connects to the rest of the ports and a 3 AN capped connection that is pointing straight up. To bleed, I leave the cap off and fill the radiator until coolant steadily flows from the fitting (it will bubble at first). Then cap the port and fill the system the rest of the way.
My system looks similar to the one below except that I am using the Earl's fittings shown above at all 4 corners (three have a single pivoting 3 AN outlet going to the distrinution block. Front driver fitting has a pivoting 3 AN connection along with the capped 3 AN bleeder port sticking straight up) and my system is connected directly to the highest point in the water pump.
Last edited by Loaded68W34; March 27th, 2022 at 02:50 PM.
The engne does not need to be running and it does not need to be warm (you could probably have it running and warm, but the rear ports may not be easy to get to so a motor that is running and hot will just make the job that much harder). You are simply allowing the coolant to push out all of the air using gravity. It will not be like bleeding brakes. The radiator just needs to be filled higher than the steam ports so that the air will be forced out when you loosen the steam port fittings. For a conventional motor like a BBO, beedling is not nesessary becuase the thermostat is the highest point. Motors with a thermostat at the highest piont can still get air pockets causing heating issues, but usually only result in false readings showing that the motor is hot when it isn't because the thermostat has not opened yet. With the LS, the highest area of the head (especially at the back) can get air trapped in it that has no way to get out without bleeding it. On my LS1, I made a system with Earl's steam vent fittings, 3 AN fittings, 3/16 stainless line, and a 5 port distribution block so that the steam vents connect under the intake and flow into the top of the water pump at the upper radiator hose exit. Even with the 4 ports connected together, I still bleed the system whenever I refill the cooling system any time I have it drained. The front driver side steam port has a swivel 3 AN port that connects to the rest of the ports and a 3 AN capped connection that is pointing straight up. To bleed, I leave the cap off and fill the radiator until coolant steadily flows from the fitting (it will bubble at first). Then cap the port and fill the system the rest of the way.
My system looks similar to the one below except that I am using the Earl's fittings shown above at all 4 corners (three have a single pivoting 3 AN outlet going to the distrinution block. Front driver fitting has a pivoting 3 AN connection along with the capped 3 AN bleeder port sticking straight up) and my system is connected directly to the highest point in the water pump.
Man that is pretty slick..I will try this next Saturday.Im at work today and will not be off until then..Thank you for all your HELP!!
I hope you can get it figured out. Bleeding the steam ports, running the motor with the heat on (allowing coolant to flow through both heater hose ports in the water pump), and checking to see that there is decent air flow through the radiator when the fans are on are simple things to try next. Also, if you did not do this already, feel the radiator hoses where they are attached to the radiator. Obviously, once the thermostat opens the upper hose should be hot at the radiator along with the radiator tank. The lower hose should be quite bit cooler where it exits the radiator. If you remove the upper radiator mount from the core support you may be able to get your hand between the radiator and condenser to feel for any hot or cold spots in the radiator. While it is unlikely with a new radiator, there is always a chance of something being clogged with heat issues like this. A digital temp gun like I mentioned earlier can help find hot areas and confirm temp readings on your gauges. Two short related stories: A freind of mine has a pro street BBC chevelle. He has a ton of money in it and it floated around several shops over a period of 10-15 years before it was finished. When he finally got it back, from a cold start he could not make it around his block before the engine temp hit 240. Turns out, one of the shops along the way masked the block to paint it and never took the masking tape off before they bolted on the aluminum water pump. Another story: My brother is into early Novas. A few years ago, he bought one in pieces. When he put it back together he could not get it to cool. He did not realize that someone had jammed a rag in the lower radiator outlet before putting the radiator hose back on. When everything was back together and he started the car, the water pump sucked up the rag.
Last edited by Loaded68W34; March 27th, 2022 at 04:36 PM.
I hope you can get it figured out. Bleeding the steam ports, running the motor with the heat on (allowing coolant to flow through both heater hose ports in the water pump), and checking to see that there is decent air flow through the radiator when the fans are on are simple things to try next. Also, if you did not do this already, feel the radiator hoses where they are attached to the radiator. Obviously, once the thermostat opens the upper hose should be hot at the radiator along with the radiator tank. The lower hose should be quite bit cooler where it exits the radiator. If you remove the upper radiator mount from the core support you may be able to get your hand between the radiator and condenser to feel for any hot or cold spots in the radiator. While it is unlikely with a new radiator, there is always a chance of something being clogged with heat issues like this. A digital temp gun like I mentioned earlier can help find hot areas and confirm temp readings on your gauges. Two short related stories: A freind of mine has a pro street BBC chevelle. He has a ton of money in it and it floated around several shops over a period of 10-15 years before it was finished. When he finally got it back, from a cold start he could not make it around his block before the engine temp hit 240. Turns out, one of the shops along the way masked the block to paint it and never took the masking tape off before they bolted on the aluminum water pump. Another story: My brother is into early Novas. A few years ago, he bought one in pieces. When he put it back together he could not get it to cool. He did not realize that someone had jammed a rag in the lower radiator outlet before putting the radiator hose back on. When everything was back together and he started the car, the water pump sucked up the rag.
Those are some crazy stories, but believable. But you might be right as far as having a bad radiator since this same one gave me the same problem with my 455..But all of this should be over in a few week's when the new cooling system and tranny get's installed..Just to let you know when my temps hit almost 250 degrees, i'll shut down the motor and keep the fans on for about 3-min's and start it back up and the temp's are around 215 degrees..So i guess with the fan's being on while the engine is off. it cool's down the coolant..And the temp drop like a rock...Never a boring moment ....LOL
I did a test last night..I let it idle with AC on for about 15-min's and let get up to 251-degrees on the top hose of the radiator...The bottom hose read 243-degrees...All done with a gun style digital thermometer. Please share your thoughts...
Seems like your radiator is not cooling properly, but an aluminum radiator that size should not be having issues like that so it is possibly a flow problem. Could be a coolant flow problem or an air flow problem. Did you have a chance to bleed the steam ports and did you have the heat on when you measured those temps? I would go out and run my wagon to take some temp readings on my radiator/ motor, but it is currently 28 degrees up here in PA. If you reach in through the bumper openings, you should be able to use a piece of paper in front of the condenser to get an idea of air flow. If that seems good, I would pull off the upper mounting plate next and feel the radiator for any cold spots. How are the fans wired? GM wired dual electric fans like I described earlier in the thread. Low speed the fans run through eachother in series to split the voltage. High speed each fan is wired in parallel to get the full voltage. It is worth investigating how your fans are wired and what is turning them on. The GM computer controlled high vs. low speed, but if you are running and aftermarket computer and GM style fan wiring, they may only be coming on in low speed. I know how frustrating something like this can be. I spent the early part of last summer getting my trans temp under control. I got the cooling system figured out, but the damage had been done so I ended up pulling the trans out to go over it (more than once) after the temp got over 300 and shredded the converter.
Seems like your radiator is not cooling properly, but an aluminum radiator that size should not be having issues like that so it is possibly a flow problem. Could be a coolant flow problem or an air flow problem. Did you have a chance to bleed the steam ports and did you have the heat on when you measured those temps? I would go out and run my wagon to take some temp readings on my radiator/ motor, but it is currently 28 degrees up here in PA. If you reach in through the bumper openings, you should be able to use a piece of paper in front of the condenser to get an idea of air flow. If that seems good, I would pull off the upper mounting plate next and feel the radiator for any cold spots. How are the fans wired? GM wired dual electric fans like I described earlier in the thread. Low speed the fans run through eachother in series to split the voltage. High speed each fan is wired in parallel to get the full voltage. It is worth investigating how your fans are wired and what is turning them on. The GM computer controlled high vs. low speed, but if you are running and aftermarket computer and GM style fan wiring, they may only be coming on in low speed. I know how frustrating something like this can be. I spent the early part of last summer getting my trans temp under control. I got the cooling system figured out, but the damage had been done so I ended up pulling the trans out to go over it (more than once) after the temp got over 300 and shredded the converter.
No time for the steam ports..Im just going to let my mechanic handle this when the new cooling system comes in..Im including a pic of my current radiator set up..As you can see there is no shroud and the fans are mounted about a quarter of an inch from radiator fins. So i believe this the cause of this heating problem...PS: Im from PA too....Pottstown Philly area..
Also, did your water pump come with the thermostat & housing?
There are 2 variations for the stat, which are different depths.
The incorrect stat could allow fluid to recirculate within the pump housing.
I recently had this happen when switching between a LS3 pump & an LSA & compared the 2 stats.... they are a different diameter & depth so the housing, stat & pump must match.
Also, did your water pump come with the thermostat & housing?
There are 2 variations for the stat, which are different depths.
The incorrect stat could allow fluid to recirculate within the pump housing.
I recently had this happen when switching between a LS3 pump & an LSA & compared the 2 stats.... they are a different diameter & depth so the housing, stat & pump must match.
Yes..It was the Holley system...But has made mistakes before...
Question I have for you, first of all, congrats on your build! 2nd of all... people would tell you what they WOULDNT DO but never tell you what they WOULD.. again!!!, do what makes YOU happy!!! Back to my question, do you still have the original cluster or did you upgrade? Thinking about doing... well I AM doing a swap but was told me keeping the original dash cluster would be a issue for the "brain"/Engine Control Module... did you go "digital"/aftermarket or did you keep it factory? If OG, HOW???
Question I have for you, first of all, congrats on your build! 2nd of all... people would tell you what they WOULDNT DO but never tell you what they WOULD.. again!!!, do what makes YOU happy!!! Back to my question, do you still have the original cluster or did you upgrade? Thinking about doing... well I AM doing a swap but was told me keeping the original dash cluster would be a issue for the "brain"/Engine Control Module... did you go "digital"/aftermarket or did you keep it factory? If OG, HOW???
Thank you!! And will respond to this when I get home..We are closing now...
I have to agree. How many Oldsmobile's among plenty of others rolled over the odometer. That didn't happen with 15 mile drives. Definitely to each their own. This thread is nails on a chalkboard for many many of us Oldsmobile fans. W-30 ragtop gets the original engine pulled and sold off...🤯
My '74 Cutlass 350 has rolled over 5 times now, on the original 350. 512000 miles and counting.
UPDATE: Got the new cooling system installed yesterday and work's like a champ!! Outside temp was 92 degrees..The hottest i could get it in bumper to bumper traffic was 192-degrees...Much better than 240-degrees...Driving at 75 -MPH temp read 187-degrees...And this is with the AC on...So my over heating problem is fixed...Next week the 4L60e go's in.... nice clean install...
Cobra2000. Nice build. I would like to know what motor mounts and headers you are using because I feel the same way you do. Out with the old and in with the new. I have a 455 in my convertible and it’s coming out. Ls is the way to go in my opinion
Cobra2000. Nice build. I would like to know what motor mounts and headers you are using because I feel the same way you do. Out with the old and in with the new. I have a 455 in my convertible and it’s coming out. Ls is the way to go in my opinion
Cobra2000. Nice build. I would like to know what motor mounts and headers you are using because I feel the same way you do. Out with the old and in with the new. I have a 455 in my convertible and it’s coming out. Ls is the way to go in my opinion
Olds 455s are finicky engines. Parts are hard to find and very expensive. They also require specialty machining and assembly techniques. They can make gobs of torque in low RPMs. If not done correctly on all aspects, the 455 will have a short lived life. I also believe an overdrive trans will lengthen the 455 reliability as it will keep RPMs down at 60MPH+
I think this is my last 455 engine. If this one fails, it will be LS engine time. A 500HP Olds 455 engine build will run around $8k-$10k for machining, parts and assembly. One can get a LS Long Block Engine with an aluminum block and aluminum heads making 525HP/ 500 FT.LBS for around $6k from Summit. Much stronger and lighter than an Olds 455 engine. An LS block can handle 1,000 HP+.
I agree with you guy's....I just want to enjoy my car and have it start and drive like it should with no problems...I work 12-15 hours days, so i don't have time for malfunctions...PS: The beefed up 4L60e was installed last week. We are just waiting for the new measured drive shaft to get here..Should be tomorrow??? I hope to have my car back by this weekend????
I agree with you guy's....I just want to enjoy my car and have it start and drive like it should with no problems...I work 12-15 hours days, so i don't have time for malfunctions...PS: The beefed up 4L60e was installed last week. We are just waiting for the new measured drive shaft to get here..Should be tomorrow??? I hope to have my car back by this weekend????
Keep us informed!
Will it have a lockup converter? If so, is it computer or manually controlled?
Cobra2000. Nice build. I would like to know what motor mounts and headers you are using because I feel the same way you do. Out with the old and in with the new. I have a 455 in my convertible and it’s coming out. Ls is the way to go in my opinion
Well my system is complete..And man talk about a smooth ride in 4th gear..The speed will get away from you if you don't watch it...RPM'S @ 70mph are 2145 and the engine sounds so quiet compared to 3200 RPM'S in 3rd gear..Before i knew it, i was up to 95mph...I did have to do some minor speedometer calibrations..Speedometer would read 80mph when GPS on my phone had me @ 83mph..I had to adjust the tire size configuration in the computer.But i did run the car through a series of test with the TEXAS HEAT. Bumper to bumper traffic 103 degrees with AC on and my temp never got over 196 degrees..So needless to say, im very pleased with my new system..Now it's time to drive and enjoy!!!
Never thought I'd see the day someone would think of doing this to a car such as this was .., of course I painted over all of my Dali's, Rembrandt's , and Picasso's, so they'd be more modern. A lot of peep's would have paid big money to have what was such a rare car and appreciated it too !
And yes, I owned a BBC powered '69 442 in 1979, but I took out the weak knee'd low comp stock sbc 350 to do the install. The original Oldsmobile 400 was on my buddy's B-I-L's garage floor with a hole thru the block. It was a $500.00 car at the time , and not many, or any, cared about originality either. But that was a long time ago too. I sold it in DFW in about 1988. I don't think it ever broke down on it's own accord even tho' the 396 was a '66..huh.
Jesse James comes to mind, (not the cowboy/robber/murderer, the other one), but you see how he comes across.
This is directly akin to having an original '67 427 435 hp Corvette convertible and yanking the engine to sell and swap-in a twin turbo subaru because it makes 600 hp !!
Do you think it was Karma that there were problems during and after the install ?? Don't think I'm being mad and hateful , cause I'm not trying to come off that way, but I am ALL of the other emotions combined...
Never thought I'd see the day someone would think of doing this to a car such as this was .., of course I painted over all of my Dali's, Rembrandt's , and Picasso's, so they'd be more modern. A lot of peep's would have paid big money to have what was such a rare car and appreciated it too !
And yes, I owned a BBC powered '69 442 in 1979, but I took out the weak knee'd low comp stock sbc 350 to do the install. The original Oldsmobile 400 was on my buddy's B-I-L's garage floor with a hole thru the block. It was a $500.00 car at the time , and not many, or any, cared about originality either. But that was a long time ago too. I sold it in DFW in about 1988. I don't think it ever broke down on it's own accord even tho' the 396 was a '66..huh.
Jesse James comes to mind, (not the cowboy/robber/murderer, the other one), but you see how he comes across.
This is directly akin to having an original '67 427 435 hp Corvette convertible and yanking the engine to sell and swap-in a twin turbo subaru because it makes 600 hp !!
Do you think it was Karma that there were problems during and after the install ?? Don't think I'm being mad and hateful , cause I'm not trying to come off that way, but I am ALL of the other emotions combined...
March 27th, 2022, 11:33 AM
