Pulling the Radiator

[Deano56]

since I have flushed the radiator twice and, the second time it seemed pretty dirty also and still the temps went up over 210 degrees, I have decided to pull the radiator, have it boiled out and if possible, add another row. Now the a/c condenser that I wanted to pull I see has the oil cooler at the bottom 2 rows. Would I be better off having a separate oil cooler and bypassing the factory placed one? I am thinking while the radiator is out, I would replace the water pump with a heavy duty high flow one, if that will help out cooling, also a new fan clutch and radiator hoses. Was thinking of getting all that air pollution stuff out of there too as the manifold tubes are starting to leak, not much but its going to get worse. What do you guys think?

[TonyMac]

Obviously, you'll be replacing the upper and lower radiator hoses, the radiator cap and thermostat bypass hose, and might as well replace the fan clutch. The lower radiator hose is subject to suction from the pump. If it collapses due to this suction, even a little bit, overheat! The hose sometimes has a spring inside to keep it from collapsing. But the radiator cap, and the pressure it allows, is also what helps keep this lower hose from collapsing.


I just replaced the pump on my '95 454. The bypass hose is not available. But I went thru the stock of hoses at my local AutoZone and found one that works great; right inside diameter and right bend. I can give you that part number if needed.

[DeOrellana]

If you're not in a state that has emission requirements, I would get rid of the SAIR system. Generally, I'm not fond of getting rid of smog stuff, but the air injection system is just a plain bad idea. You'll need to re-jet the carb (and save fuel!) of you do. To remove the air system, you can either remove the whole injector from the exhaust manifolds and replace them with plugs, or you can cut the pipes off and weld the holes shut.

The reason you need to re-jet the carb is that the carb is jetted for additional fuel to run through the motor and out into the exhaust where it is mixed with additional air and burned off. The process of burning off the unused fuel lowers the emissions.

Remember to not just flush the radiator, but also the engine and dash heater. In some cases the engine is also plumbed to heat the house heater. Open all of the heater controls so that you get a good flush. Cooling of the engine is a two step process, and most people forget that the engine needs to be able to heat the water before the radiator can cool it. If the water is not circulating through the engine correctly it will still overheat even if the radiator is up to par.

I would also add a dedicated oil cooler and a dedicated transmission cooler, depending on how much you want to spend. It's personal preference, but if something happens, it's easier to replace a smaller cooler than an integrated one. A motor home is a heavy burden for an engine, and you'll want that oil cool (not cold) and clean.

Definitely a new fan clutch. It's just cheap insurance, and if it's been on there for a while you don't know what shape the internal bearing is like.

I'm not a big fan of high flow water pumps. Some can cause the water to travel too fast through the engine so it does not have enough time to absorb the engine heat. I assume you are running a stock engine, so I would run a stock capacity water pump. The original water pump was designed for that engine as it was when it was new.

While you have the water pump off, I would take a look with a flash light inside the engine water passages where the pump mounts. They can tell you a lot about the state of the cooling system. There shouldn't be any rust in there, and if you stick a magnet in there you shouldn't get anything loose sticking to it. If you do, flush the block well.

And changing all of the radiator hoses goes without saying. I'd change the ones to the dash heater as well when you're in there.

Sorry. That's a lot longer answer than I was planning on

[Deano56]

Originally Posted by DeOrellana

If you're not in a state that has emission requirements, I would get rid of the SAIR system. Generally, I'm not fond of getting rid of smog stuff, but the air injection system is just a plain bad idea. You'll need to re-jet the carb (and save fuel!) of you do. To remove the air system, you can either remove the whole injector from the exhaust manifolds and replace them with plugs, or you can cut the pipes off and weld the holes shut.

The reason you need to re-jet the carb is that the carb is jetted for additional fuel to run through the motor and out into the exhaust where it is mixed with additional air and burned off. The process of burning off the unused fuel lowers the emissions.

Remember to not just flush the radiator, but also the engine and dash heater. In some cases the engine is also plumbed to heat the house heater. Open all of the heater controls so that you get a good flush. Cooling of the engine is a two step process, and most people forget that the engine needs to be able to heat the water before the radiator can cool it. If the water is not circulating through the engine correctly it will still overheat even if the radiator is up to par.

I would also add a dedicated oil cooler and a dedicated transmission cooler, depending on how much you want to spend. It's personal preference, but if something happens, it's easier to replace a smaller cooler than an integrated one. A motor home is a heavy burden for an engine, and you'll want that oil cool (not cold) and clean.

Definitely a new fan clutch. It's just cheap insurance, and if it's been on there for a while you don't know what shape the internal bearing is like.

I'm not a big fan of high flow water pumps. Some can cause the water to travel too fast through the engine so it does not have enough time to absorb the engine heat. I assume you are running a stock engine, so I would run a stock capacity water pump. The original water pump was designed for that engine as it was when it was new.

While you have the water pump off, I would take a look with a flash light inside the engine water passages where the pump mounts. They can tell you a lot about the state of the cooling system. There shouldn't be any rust in there, and if you stick a magnet in there you shouldn't get anything loose sticking to it. If you do, flush the block well.

And changing all of the radiator hoses goes without saying. I'd change the ones to the dash heater as well when you're in there.

Sorry. That's a lot longer answer than I was planning on

thanks for the help. The house heater hose laid on the exhaust manifold when went on our little get away week before last, kind of what started this all, that pair of hoses go 25' to under the bed. Headers and a good exhaust are in the mix here before too long, as I want to pull a car on the dolly and, they should give a little more umph. Will the carb bee too lean with out the air pumps running? We live in a none emission testing county and will not be moving. The trans has a cooler tied in the the radiator up by the grill, it's 12x12". Would I tie the oil cool in sequence or stand alone?

[DeOrellana]

Originally Posted by Deano56

Will the carb bee too lean with out the air pumps running?

Too rich

Originally Posted by Deano56

The trans has a cooler tied in the the radiator up by the grill, it's 12x12". Would I tie the oil cool in sequence or stand alone?

I would do a stand alone, i.e. not stacked. The more you stack, the more you slow down the air before the radiator.

[Deny]

New Radiator (replace what you have-no HD), new hoses, new thermostat,MAYBE new pump...not hi flow

Do not mess with air pumps etc...leave that stuff alone.

Do everything in stages...stop when it works good

Good luck!!

[Deano56]

Originally Posted by DeOrellana

Too rich



I would do a stand alone, i.e. not stacked. The more you stack, the more you slow down the air before the radiator.

i meant use both the oil cooler in the condenser and stand alone one?

[DeOrellana]

Originally Posted by Deano56

i meant use both the oil cooler in the condenser and stand alone one?

I would choose one, not both.

[Deano56]

I would think oil could be kept cooler no running through the radiator at 195

[RetireGuitar]

Yes, but sometimes too cool for proper lubrication. There’s often a designed “expectation” for certain oil temperatures to be maintained within a particular window.

Modifying oil cooling systems should only be done with careful and comprehensive consideration and perhaps some expert advice from a knowledgeable source for the application?

Too cool lube oil can often be just as damaging as too hot lube oil.

Originally Posted by Deano56

I would think oil could be kept cooler no running through the radiator at 195

[Deano56]

Originally Posted by RetireGuitar

Yes, but sometimes too cool for proper lubrication. There’s often a designed “expectation” for certain oil temperatures to be maintained within a particular window.

Modifying oil cooling systems should only be done with careful and comprehensive consideration and perhaps some expert advice from a knowledgeable source for the application?

Too cool lube oil can often be just as damaging as too hot lube oil.

what is optimum oil temperature for these big block chevys? Then we would need to talk about viscosity

[RetireGuitar]

I dunno much about big block Chevy but I’m not as concerned with engine lube oil since it’s running alongside the engine water jackets and usually warmed quickly. As general rule, 180-220F oil temps are within conservative oil temperature specs. Over 250F is cause for concern, IMO.

But what I’m talking about is mostly a concern about transmission oil temperature. In some cases the transmission lube oil is intended to be warmed via the engine coolant heat exchanger at the bottom of many radiators.

Without that engine heat exchange it can take a very long time for a transmission to warm up to operating temperature, if it ever does.

Is it a huge problem? Usually not but I would probably talk to a transmission specialist and see if they're concerned about doing away with the transmission "cooler/warmer", as the case may be?

Originally Posted by Deano56

what is optimum oil temperature for these big block chevys? Then we would need to talk about viscosity

[Deano56]

Originally Posted by RetireGuitar

I dunno much about big block Chevy but I’m not as concerned with engine lube oil since it’s running alongside the engine water jackets and usually warmed quickly. As general rule, 180-220F oil temps are within conservative oil temperature specs. Over 250F is cause for concern, IMO.

But what I’m talking about is mostly a concern about transmission oil temperature. In some cases the transmission lube oil is intended to be warmed via the engine coolant heat exchanger at the bottom of many radiators.

Without that engine heat exchange it can take a very long time for a transmission to warm up to operating temperature, if it ever does.

Is it a huge problem? Usually not but I would probably talk to a transmission specialist and see if they're concerned about doing away with the transmission "cooler/warmer", as the case may be?

I really haven't thought about the warming part of the trans lines running through the radiator. I could see if a person was to drive one of these in the cold then, the warming part would be necessary but, a warm weather coach takes little time for the transmission to heat up, usually ten minutes with mine and, that's without towing anything. I will do some checking with B & M

[BA-in-Mich]

My transmission cooler is in series with the cooler in the radiator. I installed it before the radiator and then it goes into the radiator to bring it to the temps that it needs to get to. I have a separate oil cooler on mine that is factory. I also use the 2 quart oil filter. I dont think you can add rows to the existing radiator. If your going to pull the radiator, recore it! It a PIA to pull and reinstall.