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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: swilliams on June 29, 2015, 12:51:03 am
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Hello to all. I started having heating issues this weekend getting as high as 220. I have not changed anything in months. The last thing was putting in a 160 deg tstat but again it was months ago. I have also installed a temp sending unit that came with my speedhut gauges in a spot in my intake and not in the block. I am thinking about a new radiator. I found an Eastwood radiator that sounds like it could work without spending tons of $$$. I have measured my stock radiator at 34" wide and the widest one they offer is a 28" 3 core. Will this compensate for the 6" loss. Any suggestions will be helpful. Here is a link http://www.eastwood.com/triflow (http://www.eastwood.com/triflow)
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If it occurred quite suddenly, run a compression check or cylinder leak down test. You might have the beginning of a leaky head gasket. Peer through the radiator fins and blow them out using compressed air if there are any blockages.
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Could the 220 temps warp aluminum heads
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Assuming the heads were properly torqued when installed, I think it is highly unlikely.
Are you certain the engine heated to 220°? Did you verify the temperature with an infrared or bi-metal thermometer? Were there indications other than the dash gauge?
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No I did not verify and I have also had questions about my gauges because my oil pressure is about 30 psi off from the stock gauges. I will get an infrared thermometer I have had the heads on for close to a year with no issues they were properly torqued and then re torqued. Hopefully it does end up just being a gauge issue I will run my truck or later and do the smell the exhaust test.
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I have done compression test all 8 cylinders are within 6 psi of each other. Does anyone have an opinion on the radiator being smaller but its a 3 row instead of 2 row? I mentioned it in the original post.
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No opinion on the radiator you linked since I have no experience with it. Perhaps someone else here does. From Eastwood's presentation, it is a two-core, three-pass, all aluminum design. If you think you need a radiator, a 60-day money back guarantee is hard to beat. Just keep in mind that it has no provision for cooling your automatic transmission, and because of the differences in dimension the factory fan shroud may not fit correctly. Eastwood wants you to purchase their custom shroud and e-fan to accompany their radiator, all of which will add to the cost. In addition, the radiator and fan need to be installed so that air doesn't flow around the core, but passes directly through it without recycling. You definitely don't want heated underhood air recirculating around the sides of the core back in front of the radiator or you won't gain much in the way of cooling. Neither do you want cool air blowing around the top, bottom or sides of the core, bypassing it. So, you may need to fabricate filler plates - ask them. The final thing to consider is the all aluminum construction. It's a roll of the dice whether you will encounter electrolysis. You will need to make sure all of the electric appliances, engine and cab are properly grounded to eliminate current flow through the engine coolant to ground. You should do this anyway, because of the aluminum heads. If you decide to go this route, post the process and results.
Personally, I would begin by verifying the engine temperature, before incurring the expense of replacing the radiator with all its supporting hardware....
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I am just waiting on my IR thermometer to verify temp. You did give me things to consider with the aluminum radiator. Maybe I should go with a stock replacement. By the way I did the piece of paper on the grill and the fan kept it sucked tight.
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Have you tried changing the radiator cap?
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No. What should I look for as a sign of a bad cap?
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A bad radiator cap won't cause an engine to overheat unless the cooling system is losing fluid due to a poor seal or weak pressure spring in the cap. In the case of a bad cap, it is the loss of fluid that causes overheating.
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I have used the ir thermometer and it shows that the gauge is reading correctly. Well i think so what temp should my header tubes be? They are ceramic coated. I also tried to check both head temps.
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What's the history on the current radiator?
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I have not drained it yet the heating started cind of quickly. I have run the truck with the cap off to check for trapped air things seem to look good. Nothing floating no rust or build up.
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I have used the ir thermometer and it shows that the gauge is reading correctly. Well i think so what temp should my header tubes be? They are ceramic coated. I also tried to check both head temps.
So, aiming the IR thermometer at the t-stat housing verified 220° F? Here are some things to check...
- Is the radiator full of coolant?
- Have you looked through the radiator fins using a backlight to ensure the fins are clear and there are no obstructions to airflow?
- While the engine is running at operating temp, do you feel any cold spots moving your hand across the front of the radiator? There should be a gradual drop in temperature of ~20° from driver side toward passenger side with no obvious cool spots across the core.
- Does the t-stat begin to open at its rated temperature?
- Looking into the radiator from a safe angle with the cap removed and engine warmed up, does the coolant level drop 6" - 8" as you increase engine RPM to +2,000? Be very careful while doing this to avoid scalding water - let the RPM back down gradually so hot water isn't ejected from the radiator. This is an indication of coolant flow.
- With a pressure tester attached to the cold radiator, how quickly will the cooling system build pressure on its own to 16 PSI with the engine running? Does it build above 20 PSI?
- When the engine is running hot, what does the gauge do if you flood cold water from a garden hose across the radiator core?
- With the engine off, if you grab the tip of a fan blade and wiggle it fore and aft, is there more than ~3/16" play? Does the fan clutch offer resistance if you try to spin the fan?
- Are the fan belts tight?
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I would ask a pro first. There pretty cheap however they can screw your radiator up! Hope this helps.
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BD thanks! I didn't know about radiator caps. Just to a guess. Lol
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You're welcome.
For an additional tidbit... besides functioning as a two-way check valve in the closed cooling system, the radiator pressure cap raises the boiling point of water about 3° F for each pound per square inch of pressure increase above the ambient pressure. So, a 16 PSI pressure cap will raise the boiling point of water roughly 3°/PSI x 16PSI = 48° F. At sea level that amounts to 212° + 48° = 260° F for pure water.
But, a 50/50 mix of glycol antifreeze and water boils at about 8° F higher temperature than pure water. So, at sea level, a 16 PSI pressure cap on the typical automotive wet cooling system that contains a 50/50 mix of antifreeze and water will boil at about 268° F. That's pretty hot!
In summary, a weak radiator pressure cap won't cause coolant temperature to increase, but it will allow the liquid coolant to boil at a lower temperature than intended, which could expel coolant from the system. The resulting loss of coolant, if sufficient, will cause overheating.