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Discussion Starter #1
Hi all, warning, more noob questions :)

It appears I have a slight coolant leak but need to know what to replace. In the pic below you will see it looks like it might be coming from the hose. That clamp is tight. Should I replace the hose?

What type of coolant do you use in these engines? Same as modern cars?



The radiator is full of coolant, but this little container is empty. And what is the black one for?



Thanks
 

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Black bottle is for washer fluid. The other one is a home grown shade tree engineered catch tank. If the radiator is full leave it alone, it has plenty. Originally there was no catch tank and a couple inches below the radiator cap would have been normal level for coolant. As for the thermostat housing. It could have pits from corrosion and not sealing well against the hose. It could be the hose or the clamp. If you replace any of it I would replace the thermostat and the gasket plus what ever is wrong. No sense in doing things twice.
 

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Discussion Starter #4
If I undo that hose will coolant pour out? Will I be able to tell what temp that sensor is?

Thanks
 

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Discussion Starter #6
I assumed I am supposed to take those 2 bolts off and there is a thermostat in there? I mean if I removed those bolts then will coolant start spilling out? And there are many thermostats listed, so I would need to know what temp this one I have operated at.

What does ARP mean?
 

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If you want good heat 185 to 195. I run my cars cool at 165 or no Stat at all. You need to drain out some coolant from the radiator before you remove the 2 bolts on the housing that the hose goes into. Like an oil pain full. The bottom of the radiator inside by the engine should have a petcock to drain from. 185 should be about an all around good temp for almost any older V8. It should be stamped into the old thermostat around where the gasket goes as to what temp it is. You can put it in a pot on the stove heat it up with a temperature gauge/ thermometer in the pot with it and watch when it start to open.

If you look at the top of the bolts holding the thermostat housing and the intake there is ARP printed on them.
 

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coolant leak is due to water neck being cast iron while intake is aluminum, should use an aluminum water neck so dissimilar metal expansion is not causing the leak. Based on the questions, a service manual would be a help for this learning curve. downflow radiator, lose the home made overflow tank unless you are running at the track. Antiseize the bolts on the water neck as well as put sealant on the gasket as well as the hose. Hose is pushed too far down on the neck which causes it to flare out.
 

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ARP is a brand name of top quality hardware (nuts and bolts) Yes,you have a leak, it looks like at least the hose connection, possibly thr T-stat housing also. Housings are $25 new, t-stats cheap, and hoses $20ish....I would purchase the parts and lovingly replace all 3...but I tend to "over repair" stuff....must be the helopilot mentality.:cheers Eric
 

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Discussion Starter #10
Thanks guys, looks like I'll just replace everything. Parts are cheap enough, so well worth knowing the problem is fixed.

What type of sealant should I use?
 

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Batman ..... Do this: Replace the thermostat with a high flow 165* one from NAPA.. (stant). You will get a gasket with it. Clean the neck of the housing. Lightly sand the neck to remove any burs. Make sure its smooth. You don't need to but if you have some form a gasket lightly place some on the underside of the thermostat housing and carefully place atop the gasket. This is added protection. Tighten the bolts evenly. Place a small amount of 50/50 Prestone type anti freeze into the neck. Then place the hose back on the whole way down and use a new worm screw clamp. The heat from the motor will help the form a gasket set up... You may want to consider using a bottle of water wetter in the 50/50 mix of anti freeze in the radiator.

I use the 165* thermostat I have no issues at all... I get plenty of heat and on a 70-80* day I run about 165-170*. On the hottest days this year I never got above 190*.
 

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coolant leak is due to water neck being cast iron while intake is aluminum, should use an aluminum water neck so dissimilar metal expansion is not causing the leak. Based on the questions, a service manual would be a help for this learning curve. downflow radiator, lose the home made overflow tank unless you are running at the track. Antiseize the bolts on the water neck as well as put sealant on the gasket as well as the hose. Hose is pushed too far down on the neck which causes it to flare out.
i dont see any rust on the housing. looks like the one i have thats made from aluminum. its bolted to a cast iron intake. what was john delorean thinking?
 

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Just replace the gasket, and put a little blue RTV on the gasket, it's just a little leak. Also, clean the area that the hose mounts so it seals better, looks easy. You said it runs cool, leave the thermostat alone. It's going to dump the water in the hose and to that level in the radiator. Leave the overflow can in place, the old school cars didn't have one, but the rads were always an inch or so low, nice upgrade from none..
 

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Discussion Starter #15
If I put a nice coating of RTV on there it will stop the 2 different types of metals from touching and rusting? I think that is the main reason why they were saying to replace the housing too.

It runs cool, here is a pic after driving it an hour (temps will rise to 200 if sitting for like 10-15 minutes):

 

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Your pics dont' show a leak, nothing wet, they just show where something leaked in the past. Are you losing water?
Just put a new gasket in it and a very small amout of RTV, it will seal. Don't use too much RTV, trust me, people see it.. They are dissimilar metals, but all is good, your gasket is leaking. You don't need to get all the parts.. If it still leaks you might have to flatsand the gasket surfaces, but I'm sure it won't come to that, been there done that, never looked at it again..:cheers
 

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Permatex #2 gasket sealer, no RTV. "Leave the overflow can in place, the old school cars didn't have one, but the rads were always an inch or so low, nice upgrade from none" Actually downflow radiators are not meant to be full, which is why the factory had the level marked for where full is. Now the crossflow ones are filled because the cao is on the return outlet tank side of the tubes, which is why crossflow have overflow on them to keep air pockets out.
 

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Discussion Starter #18
Anyone know what type of temp sensor I have? I've never sen one without a plug. Seems mine has stopped working :( Worked fine Thursday, when I started it up today it never moved. I even took the temp gun out to verify it was up to temp (I drove it 6 miles, so it should have been). I was getting about 160* at the sensor.

 
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