running hot - am I way off here?

[bridges]

Brief History - '82 Land Cruiser purchased with '85-'87 Chevy 350 (dead motor), installed '92 Chevy 350. Water pump on old engine had a return line port on the top, new one doesn't cause the '90s chevy trucks had the return line at the top of the radiator.

Things I've tried:
- lower temp thermostat
- higher temp thermostat
- no thermostat
- by pass heater core (thinking it was clogged)

My concern is that my only place to hook up the return line on the current configuration is the side of the block (commonly used for block heater lines)

Does anyone else here think that I may be running a little hot (almost 220 degrees) due to the small size of this inlet 3/8" as opposed to the 3/4" inlet on the old water pump or '90s Chevy radiators?

See here:

 

[bridges]

new return line location

I'm thinking I could tap and install a 3/4" nipple here for the return line in the top of the radiator:

Good idea, bad idea?

THANKS!!!

 

[Elbert]

you have some kind of "nipple" setup in the freeze plug?

is that a GM TBI motor? Are you using the OEM intake and thtottle body setup...if you are not and you are using one of the intakes for a carb setup can't you install a nipple fitting in one of the accessible holes in the intake?
like most of the old 350 engines had?

Coolant flows from the rear of the intake...through the heater core then back towards the radiator or back towards the front of the intake like on a car? I think thats right...or exactly the opposite.

220 is hot.... I dno't think that problem has anything to do with your heater hose return issue.

Install a 180 degree thermostat... What type radiator and fan are you using?

I have a 92 K1500 with a 350..it runs fairly cool but I've made some changes to assit that... I would not accept 220 as normal. Truck should run between 190 and 210 in the summer, maybe a little warmer under heavy use, with that engine.

 

[bridges]

Non TBI, intake is for a carb setup. I'll try and research more online for your suggestion about running it back into the intake somewhere. Rookie engine installer here so I'm learning on a regular basis.

Tried 180 degree thermostat and someone suggested a higher temp to let the water spend more time in the radiator to cool (worked for them), but the 195 degree thermostat didn't change a thing. Running no thermostat at this exact moment with the heater core bypassed.

I think you were right about the reverse of your description, there is one opening towards the back of the intake manifold that I could probably use as the return point.

With the inlet on the bottom the hoses do run close to the exhaust too, but at the closest point it's just over an inch away.

EDIT: Answers to your other questions - Factory radiator I believe and I'm a running a 16" electric fan as a puller, but when I was still running hot I put the fan from the old engine on as well (no change in temp).

 

[Elbert]

well I'll post this again somehow I screwed up...maybe this will not go out twice.

your intake has a port on the rear RH side for a heater hose which I assume you are using. The old-school intakes for carb setup have a port at the RH front of the intake for a heater hose. One is 5/8 and the other is 3/4. This is where your heater hoses go if the intake support that. If not then you most likely will need to change the water pumpt to one that has the port on it.

Take the freeze plug thing out.....this is not the way to do that. Either intall a new freeze plug and or block heater ....

Install a 180 degree thermostat

If you are running that clutch fan then you need a radiator shroud ( no exception) the truck will not pull enough air across the radiator without a shroud!

What happens with you take the clutch fan off and just run the electric fan? Is this fan sucking air through the radiator? like it should? hopefully you have the electric fan on a relay and some type of temp sensor controller?

I would seriously doubt that the OEM radiator can cool a GM 350 very well.


I would remove the clutch fan if you can't adapt a proper radiator shroud because if you can't the fan just is not going to work. I then would get the largest single electric fan or combinnation of elctric fans to use on that radiator. You see my other post about a fan flex-a-lite makes for those year model trucks? (but they don't say anything about V-8 conversions running the original radiator?

Take the clutch fan and clutch off. On that year model engine you should have 4 nuts that hold the clutch on to the waterpump pulley... Remove clutch and fan. Install a couple of good washers on each stud and then tighten the 4 nuts back down on the water pump pulley where the belt is straight and the pulley is tight.

then proceed on with an electric fan setup. Or if you have too.... Remove both the fan clutch and fan, and the electric fan and obtain a "flex fan". If you run a flex fan you need to pay attention to the instructions about proper spacing of the flex fan in relationship to your radiator...they make various length spacers for this purpose.

Personally I would look into what others are doing on cooling with a V-8 engine swap. I would imagine that the radiator has to be changed? and you need some good electric fans to move the air across the radiator...

no radiator shroud = no radiator clutch fan (just will not work right)

another general observation is that your fan clutch needs an air path across the front of it in order for it to work...because the fan clutch senses the temp of of the air coming across the radiator, which I'm guessing is a little hard for it to do given the current setup.

connect the heater core back up it has no affect on your overheating problem.

If you don't want to run a heater then cap off the heater hose ports with some pipe plugs and that would be the end of your heater hose problem. Personally I like a heater to work in the winter time.

220 is to hot..... that OEM radiator was not make to cool a V-8, that most likely your problem along with insufficient air-flow across your radiator due to lack of a fan shroud.

Electric fans come in two styles.... a pusher or a "puller" either its pulls air through the radiator or it pushes air through... on the rear of the radiator the fan should pull air...on the front of the radiator it should push air or force air across the radiator. I'm not one that believes a fan performs as well in either direction just by reversing the wiring as some say.

Look up any old 350 engine for example a 78 z/28 ...you'll see that the heater hoses connect to the intake (both of them) and some older cars used the water pump as one source. Any parts store would know that....the key is one is 5/8 in size while the other fitting is 3/4 in size ( the threads are the same, the nipple side is different).

I'm not sure it really matters what direction the water flows through the heater core...just as long as it does, if you want the heater to work. You need to solve your cooling problem first. I would also suspect that you have a potential problem with whatever that is you have in the freeze plug area above the starter.

Post what you find out and I'll try to help if you need / want further comments.

 

[Elbert]

well I'll post this again somehow I screwed up...maybe this will not go out twice.

your intake has a port on the rear RH side for a heater hose which I assume you are using. The old-school intakes for carb setup have a port at the RH front of the intake for a heater hose. One is 5/8 and the other is 3/4. This is where your heater hoses go if the intake support that. If not then you most likely will need to change the water pumpt to one that has the port on it.

Take the freeze plug thing out.....this is not the way to do that. Either intall a new freeze plug and or block heater ....

Install a 180 degree thermostat

If you are running that clutch fan then you need a radiator shroud ( no exception) the truck will not pull enough air across the radiator without a shroud!

What happens with you take the clutch fan off and just run the electric fan? Is this fan sucking air through the radiator? like it should? hopefully you have the electric fan on a relay and some type of temp sensor controller?

I would seriously doubt that the OEM radiator can cool a GM 350 very well.


I would remove the clutch fan if you can't adapt a proper radiator shroud because if you can't the fan just is not going to work. I then would get the largest single electric fan or combinnation of elctric fans to use on that radiator. You see my other post about a fan flex-a-lite makes for those year model trucks? (but they don't say anything about V-8 conversions running the original radiator?

Take the clutch fan and clutch off. On that year model engine you should have 4 nuts that hold the clutch on to the waterpump pulley... Remove clutch and fan. Install a couple of good washers on each stud and then tighten the 4 nuts back down on the water pump pulley where the belt is straight and the pulley is tight.

then proceed on with an electric fan setup. Or if you have too.... Remove both the fan clutch and fan, and the electric fan and obtain a "flex fan". If you run a flex fan you need to pay attention to the instructions about proper spacing of the flex fan in relationship to your radiator...they make various length spacers for this purpose.

Personally I would look into what others are doing on cooling with a V-8 engine swap. I would imagine that the radiator has to be changed? and you need some good electric fans to move the air across the radiator...

no radiator shroud = no radiator clutch fan (just will not work right)

another general observation is that your fan clutch needs an air path across the front of it in order for it to work...because the fan clutch senses the temp of of the air coming across the radiator, which I'm guessing is a little hard for it to do given the current setup.

connect the heater core back up it has no affect on your overheating problem.

If you don't want to run a heater then cap off the heater hose ports with some pipe plugs and that would be the end of your heater hose problem. Personally I like a heater to work in the winter time.

220 is to hot..... that OEM radiator was not make to cool a V-8, that most likely your problem along with insufficient air-flow across your radiator due to lack of a fan shroud.

Electric fans come in two styles.... a pusher or a "puller" either its pulls air through the radiator or it pushes air through... on the rear of the radiator the fan should pull air...on the front of the radiator it should push air or force air across the radiator. I'm not one that believes a fan performs as well in either direction just by reversing the wiring as some say.

Look up any old 350 engine for example a 78 z/28 ...you'll see that the heater hoses connect to the intake (both of them) and some older cars used the water pump as one source. Any parts store would know that....the key is one is 5/8 in size while the other fitting is 3/4 in size ( the threads are the same, the nipple side is different).

I'm not sure it really matters what direction the water flows through the heater core...just as long as it does, if you want the heater to work. You need to solve your cooling problem first. I would also suspect that you have a potential problem with whatever that is you have in the freeze plug area above the starter.

Post what you find out and I'll try to help if you need / want further comments.

 

[Elbert]

just to make clear... one heater hose connects to the rear of the intake....

the other heater hose connects to the front of the intake or to the water pump if you have to do that (or on trucks to the radiator)

One of the fittings is 5/8 and the other is 3/4. Parts house shoud now which is which. Not sure what you'll have to do on the yota since I'm not sure what size the heater hoses are but you'll need to match the fittings to the hose size.

 

[ERICH]

I didn't read all of the replies, but if that is an old TLC radiator then it may be restricted. You need a lot of cooling capacity for a 350. Flushing kits don't really do it. THose radiators last forever and they get blocked before the leak. I always take them out and flush them a solution of muraitic acid, search on here I did a post on it a few years back.
Good luck.
ERICH

 

[bridges]

Excellent information, thanks Elbert and Erich!

I'll be routing back into the intake manifold this weekend and will post up on Monday how it turned out.

I'll take the fan off the motor and just leave the temp controlled electric fan on there. I'll put the 180 degree thermostat back in also. PO swears it ran cool with this radiator so it may just need a removal/flush with acid. I'm getting a clean green at every point in the system so I really hope that moving the return line to the back of the intake and away from the exhaust will help. If not, I'll remove and flush.

I work from home so the most driving I will be doing this week is to the local corner store and it doesn't have time to really heat up before I'm back at the house.

 

[Dynosoar]

In your first picture where it says "current return line location" that thing above the starter is the knock sensor. That sensor is needed on all fuel injection motors. What it does is sense knock and sends a signal to the computer to retard your timing. If your timing keeps advancing you will get a knock and excisive heat build up in your engine.

Dynosoar

 

[bridges]

I didn't have a picture after that was removed, this engine is no longer fuel injected so I installed a nipple here as a return line for the coolant. I used the nipple utilized by the old 350 for the block heater.

 

[Elbert]

ok....

just some additional.. info

the heater hose from the rear of the intake should run to one side of the heater core, normally the one closest to the engine, the other side of the heater core /heater hose should run to the front of the intake or to the water pump (old school) if the pump has a "port" to istall the nipple.

If you can take a picture of the intake on the RH front side where we can see the water neck and the area around the water neeck on each side of the intake.

I'm just doubtful that the PO had that truck running "cool" with the seutp is has now? I think your radiator will turn out to be the problem...its not large enough...to cool a 350.

 

[bridges]

Thank You!

Had some plans fall through tonight and was able to free up some time to work on Frankenstina!

Not sure what portion was the resolution but she is steady now and running as expected!

1. Install Thermostat - Couldn't find my lower temp thermostat so I installed the 195 (live about 35 minutes from an autoparts store so I'll pick up the lower temp this weekend).

2. Removed engine mounted fan and I'm running an over the counter 16" electric fan with the wiring reversed to convert it to a pulling fan.

3. Rerouted the hose closest to the engine directly into the intake manifold at the rear 5/8" port, the other heater hose goes to the larger port at the front of the intake. (I'm still questioning this one and may reverse them because I have no heat from the heater) I will research this first and probably go to an end of the road car lot to find an '80s chevy truck to compare.

I let the truck idle for about 30 minutes, checked all of my hose connections for leaks and then went for about an hour drive and she maintained a temp at 195 degrees!!! Everytime it would start to creep just above the thermostat worked as expected and the temp went right back down. Never above 200.

Thanks for all of the pointers and information, truly helpful in resolving one of those pesky issues that has kept me from driving the truck any real distance.

Currently 83 degrees outside so I'm anxious to see how she'll do tomorrow afternoon on a similar drive when it's still in the 90s and I throw in some stop and go traffic.

 

[bridges]

It's official

95 degree weather, just over an hour drive with speeds up to 65-70 and about 20 minutes of stop and go traffic and no rising temp, stayed right at 195 again!!

Thanks again for the help!