Need help with overheating issue on my 77 k10 with sbc 350

[SquareRoot]

Well I used a block tester and fluid did not change so head gasket should be good, I had already ran that test but forgot to put in original post. I have a fan shroud. It runs hot all the time my gauge used to peg hot right away but after replacing tatar and water pump gauge slowly gets hot and it seems to stay between 3rd hash and just before where the red starts. I'm thinking its my rad cause all my horses are good I have no leaks

Taters and horses will do it every time!

 

[chengny]

Well I used a block tester and fluid did not change so head gasket should be good, I had already ran that test but forgot to put in original post. I have a fan shroud. It runs hot all the time my gauge used to peg hot right away but after replacing tatar and water pump gauge slowly gets hot and it seems to stay between 3rd hash and just before where the red starts. I'm thinking its my rad cause all my horses are good I have no leaks

Do this simple quick test to check for fouled watersides of the radiator cross tubes. It will also confirm adequate water pump flow and proper t-stat operation;

1. With the engine cool, open the radiator fill cap. Leave the cap off.

2. Drain off enough coolant so that the level in the radiator is about 1/4 down - so you can see a few of the tube ends.

3. Start the engine and allow it to reach normal operating temp.

4. When normal operating temp has been reached, look down through the radiator fill neck. Observe whether a good stream of coolant is flowing out of the ends of the tubes and into the outlet tank. If it is, that would confirm that the t-stat is opening fully and at the correct temp.

5. Next, have your assistant rev the engine up/down while you observe the level in the outlet tank. When the RPM's are increased, two things should happen:

a. The volume of water issuing from the tube ends should increase substantially and

b. The level in the outlet tank should fall noticeably

6. When the RPM's are allowed to return to normal, the coolant should quickly rise back up to the initial level.

While you have the cap off and the level is down, inspect the ends of the tubes carefully using a flashlight. Note whether there appears to be any deposits that have formed. If so, you can be almost sure that the watersides have become coated all the way across.

Keep in mind however, that sometimes, even when there is sufficient flow through the tubes, heat transfer is inadequate due to the film of mineral deposits.

 

[Snoots]

This is a hoax.
No problem exists.

No pics. Humph!

 

[chengny]

Oh yeah - and I think this was already noted in a previous post - the depth of the fan blading into the shroud throat is very important.

1. If the blades are set too far into the shroud, a recirculation effect develops.

Say you have excessive clearance between the blades and shroud (this happens because of the way the shroud is tapered - the throat gets larger as it nears the radiator). Instead of being diverted away - into the engine compartment - some percentage of the air flowing out of the fan's discharge side recirculates (through the shroud/blading gap) straight back to the suction side. So, while fan capacity remains constant, the flow of air across the radiator is reduced - by the amount being allowed to recirculate.

2. This one is simple.

Say the fan is set too far back - so much so that a big gap exists between the blade tips and the shroud opening. Instead of pulling its full flow of air through the radiator/shroud as it should, the fan takes some amount (how much depends on the degree of set back) from the engine compartment atmosphere. Same result as above: while fan capacity doesn't change, flow through the radiator is reduced by the amount flowing in from the engine compartment.

Proper clearance is shown below:

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[Lens77chevy]

I have not verified temp with a laser due to not having one. While sittingvtruckvruns right at the start of the red on gauge and while driving it's closer to the third hash mark. My fan set up is just the blades bolted to the water pump driven by belts and harmonic balancer and a stock plastic shroud. There may be some gaps between shroud and support, I will check tomorrow along with a bag and tissue paper test. I also interviewed at autozone today, a part discount would be sweet

 

[1987 GMC Jimmy]

That’s about how my gauge reads with the screwy temp circuit even though it runs at a perfect 195*. Not saying that’s you necessarily, but I wouldn’t have known without a thermometer to verify. You can get a little cheapie at Harbor Freight for around $11-$13 and a decent one that’ll last from Home Depot for about $30.

 

[Lens77chevy]

Here are the pics of my fan set up I noticed a gap between support and shroud I'm gonna tape it up this morning

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[CSFJ]

Fan installed backwards?
Upside down?
Inside out?

Ah!
Radiator hose collapsing on itself mebbe? Does it gots a sprang in it?

Your flow is all jacked up somewhere ol boy. You ain't got none.

None.Flow.

Rusty asked this on the first couple of responses. I didn't see an answer, perhaps I missed it.
Did you ever verify wether or not the spring is still inside the lower hose?

 

[Lens77chevy]

Spring is in lower hose I didn't verify fan being on correctly but I believe its is also here is a pic of my normal running temp as of late

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[da_raabi]

Here are the pics of my fan set up I noticed a gap between support and shroud I'm gonna tape it up this morning

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That fan looks waaaay too far back. Look at the images chengny posted. That guy knows his stuff.

If your fan is on all the time then dollars do donuts its not original. Whoever installed it probably was not paying attention to fan depth. It looks to me like your fan could use a little spacer to get it into the shroud more. Notice how chengny's only protrudes about an inch or so? Yours protrudes by about 3/4 of the fan. Yeah. That's not going to work too well.

I'd spend the money and get a nice new OEM heavy duty clutch fan. Guarantee you will never have an issue again!

 

[da_raabi]

I also noticed that your radiator is friggen puny. Is that stock? I know mine is a big block rad, but I swear its gotta be 3 inches taller and about a foot wider!

 

[Lens77chevy]

Idk if rad is stuck or not I bought this thing 2 months ago and the kid seemed like a schmuck. There are toggle switches everywhere, a wiring nightmare so I'm not sure what all he did to it

 

[Lens77chevy]

And thank you all for your responses I really appreciate your help

 

[Snoots]

That fan looks waaaay too far back. Look at the images chengny posted. That guy knows his stuff.

If your fan is on all the time then dollars do donuts its not original. Whoever installed it probably was not paying attention to fan depth. It looks to me like your fan could use a little spacer to get it into the shroud more. Notice how chengny's only protrudes about an inch or so? Yours protrudes by about 3/4 of the fan. Yeah. That's not going to work too well.

I'd spend the money and get a nice new OEM heavy duty clutch fan. Guarantee you will never have an issue again!

I didn't notice that a clutch was installed. Fan does look too close to the engine. It should be just inside the shroud.

 

[Lens77chevy]

No clutch on fan