My K20 would always overheat when runnin' the snot out of it in the mud. I just put a new thermal fan clutch on it (it has a factory style 5 blade fan) and a fan shroud with the bottom trimmed because of a 3" body lift. My temp gauge is new also. After about 1/2 hour of running 3000 to 4000 rpm in the mud the highest the temp made it to was 220 degrees. Is this ok or should it be lower? (stock 350, 3 core radiator, about 50 degrees outside) I plan to take out the a/c coil in front of the radiator, would this help at all?
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Is 220 degrees ok?
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big83chevy4x4
3/4 ton status
my opinion is 220 is fine. mine runs about 200-215 most of the time (195 stat) 220 with the plow on
84_Chevy_K10
Banned
220 is fine. I wouldn't worry unless it exceeds 240. As long as it cools at idle now you're good.
The a\c condenser could be restricting the air flow a little. What condition is the Radiator on the inside? It could be plugged with crap.220 is not bad but a little high. what temp range is the stat?
dirtwarrior17
Banned
220 is good enough as long as it doesn't get hot goin up long hills on the freeway. If you want it cooler get a 165 stat or run some of the radiator coating crap called Be cool. supposed to lower temp by UP TO 40 degrees. Most thermostat actually open up at 5-10 degrees hotter than they say.
I have a 195* thermostat and the inside of the radiator doesn't look too bad. It runs about 190* under normal driving conditions, and you guys say that 220* is ok in the mud so I'm not going to worry much about it anymore. Now I can save up a bit more money and buy a steering brace and brake lines, I may contact the parts pimp after I have enough cash. 
dirtwarrior17
Banned
Well it's up to you but the cooler your motor runs the more life it will have down the road. A 165 stat is 15 bucks in jegs.... be at your door in a week with free shipping.
TBI likes the hotter temp, thus the factory 195..
pauly383
Daddy383
The only way I could see 220 being ok is if you run an automatic transmission in Arizona , trying to climb loose dirt hills and get it really hot . Then it goes back to normal after you stop and never sees 220 degrees again until you do the same .
OR ..... if you are in the mud and radiator gets blocked by mud . You need to pull over from playing and let it cool down . Now if its running that hot all the time , there is a problem .
Engines can live at that temperature , but if you aren't making Nascar power and forcing the air through a nostril it doesn't need to run that hot .
Maybe reengineer the fan shoud also so it does its intended job .
Post meant as an opinon and my own feelings
OR ..... if you are in the mud and radiator gets blocked by mud . You need to pull over from playing and let it cool down . Now if its running that hot all the time , there is a problem .
Engines can live at that temperature , but if you aren't making Nascar power and forcing the air through a nostril it doesn't need to run that hot .
Maybe reengineer the fan shoud also so it does its intended job .
Post meant as an opinon and my own feelings
fatbob
1/2 ton status
[After about 1/2 hour of running 3000 to 4000 rpm in the mud the highest the temp made it to was 220 degrees]
If thats the highest temp it got when your running it that hard, then your doing pretty good IMHO
If thats the highest temp it got when your running it that hard, then your doing pretty good IMHO
fatbob said:
Yep, I didn't let up unless I was shifting from d to r while turning around. The whole time I had a rod knocking and runnin' about 15 PSI of oil pressure. This old motor has been knocking for about 6 months now but just won't come apart!
sounds pretty good for an old motor like that. if it was me i'd still throw in a lower thermostat. i replaced the stock 195* unit with a premuim 180* stat in my truck. makes me feel alot better seeing the needle farther away from the 210* markdivorced said:
BURBicon
Registered Member
My truck tends to run hot on the interstate. It gets up to about 220* pretty quickly and stays there when I'm driving 65-ish. I notice a slight loss of power and some pre-ignition ping, so I ease it down to 55-ish and it cools down and goes back to normal.
Lower thermostat is a crutch only, and will do nothing to change your cooling efficiency.
If you've got a new radiator to put in, do that, and see what happens.
Once the temperature of the engine/coolant exceeds the rated temp of the thermostat, it's wide open. Doesn't matter if you have a 160* stat or a 195*, once coolant exceeds those temps, the stats don't do a thing for cooling.
If your engine can't keep cool with a 195*, it can't with a 160* either. The ONLY difference is that if the engine runs at 160* on flat ground, but you need to climb a hill and temp starts to climb, you have a 35* "cushion" that gives you that much more time before it gets to whatever temp it either equalizes at, or when you decide it's getting too hot.
If you've got a new radiator to put in, do that, and see what happens.
Once the temperature of the engine/coolant exceeds the rated temp of the thermostat, it's wide open. Doesn't matter if you have a 160* stat or a 195*, once coolant exceeds those temps, the stats don't do a thing for cooling.
If your engine can't keep cool with a 195*, it can't with a 160* either. The ONLY difference is that if the engine runs at 160* on flat ground, but you need to climb a hill and temp starts to climb, you have a 35* "cushion" that gives you that much more time before it gets to whatever temp it either equalizes at, or when you decide it's getting too hot.
dyeager535 said:
this is true, but they say cheap thermostats can open 5-10* hotter and advertised. so your 195* is now a 205*. most carb motors make max power running around 180*, so i dont think its a crutch to go with a 180*stat. if your putting a 160* stat in, then ya.... thats a crutch.
Jonny-K5 said:
I don't think you understand what the other guy was saying. The idea of a "crutch" has nothing to do with running the correct temp. thermostat for the engine. What he was saying is that if the cooling system can't keep the engine from overheating with a 190 stat, then it still won't be able to keep it cool with a 160 stat.
In regards to "cheap" thermostats, if one can open 5-10 degrees hotter than advertised than it is also just as likely that another one of the same brand with open 5-10 degrees cooler than advertised. There is nothing inherit in the design of thermostat that would make a cheap version always open at hotter temperature. The tolerance in the manufacturing of the thermostat can easily go either way (hot or cold). But overall I agree, cheaper thermostats can easily open at 5-10 degrees + OR - the adverstised temperature.
If the motor can only manage 15psi of oil pressure and is knocking than who care what temp it is running at. I would be more focused on getting the funds and/or parts ready to build an new engine, cooling system, and transmission if need be.
If the current engine is knocking it will probably toss in the towel soon and the longevity of te head gaskets don't really matter so I say 220* is fine until it comes apart soon.
If the current engine is knocking it will probably toss in the towel soon and the longevity of te head gaskets don't really matter so I say 220* is fine until it comes apart soon.
6.2Blazer said:
i understand completly what the other guy is saying.i was simply making two points. i personally feel that 180 stat is better overall for longevity and horsepower reasons, not to use it as a crutch.
your right,cheap stats could open 10* cooler as well. i didnt say it was inherit that a cheap one will always open hotter, just that it can. so if you have a finicky cheap one in the cooling system, and its not opening when it supposed to, then it could causs the motor to spike to higher than normal temps. maybe it sticks sometimes and doesnt open til 220. im just saying that i would put a premium stat in, that is tested to open within 2* or advertised rating, and get one that 180, just causs its better for the motor anyway. i only real reason(in my opinion) they use 195 stat stock is to produce lower smog levels.
Expansion of metal MIGHT be part of the temp scheme, as I believe GM has/had been using 195* stats WAY before emissions got serious in the mid-70's. I could be wrong about that, I know some vehicles had AIR as early as the 60's. I have no clue though if cast iron expands enough in a 15* temp swing to affect tolerances. As I've heard it, the SBC runs pretty "loose" tolerances (compared to newer stuff or other brands) from the factory anyways.
Some book I read at one time quoted a GM study that showed the differences in power between 160 (or 180, can't recall exacts) and 195* were almost nonexistent.
Heat makes power.
Besides the fact, as big as the inside of a K5 is, all the extra coolant heat is nice for the interior, at least for me.
As long as your cooling system can keep the vehicle at rated t-stat temp, no, running a colder stat is not a crutch, just personal preference. I know plenty of people run lower temp stats for long periods of time. Just like anything else though, there are SO many variables, even if the 15* difference (for instance) caused more wear to bearings, whatever, there would be no way for us to know, or prove it.
Some book I read at one time quoted a GM study that showed the differences in power between 160 (or 180, can't recall exacts) and 195* were almost nonexistent.
Heat makes power.
Besides the fact, as big as the inside of a K5 is, all the extra coolant heat is nice for the interior, at least for me.
As long as your cooling system can keep the vehicle at rated t-stat temp, no, running a colder stat is not a crutch, just personal preference. I know plenty of people run lower temp stats for long periods of time. Just like anything else though, there are SO many variables, even if the 15* difference (for instance) caused more wear to bearings, whatever, there would be no way for us to know, or prove it.
