Cooling issues?

[seadog]

Along with my hydroboost problem it got hot today on the test run.Drove it 2 miles and it got hot.This is on a 55 degree day with flowkooler pump,16# cap,160 hi flow stat,80/20 water to antifreeze with water wetter additive.I dont know much about clutches but it would spin freely while it was hot.I used the old radiator because it was fine before rebuild.All the other parts are new.(no shroud)Maybe try a flex fan ?

[steven79]

160 t-stat is to low you need min 160 t-stat , i am running a 195 in mine with a heavy duty fan clutch and it never gets over 210 at hi speed and sits at 195 when crawling in the hill here in tx.

[steven79]

sorry i said 160 min 180 t-stat
and you can get a hd fan clutch from a chevy motor home and cut the bolt holes out to make it fin the water pump.
also leave the cap off and let it warm up so it can burp all the air out of the system

[seadog]

I thought the lower the stat the sooner it would open up?I will definately do the open cap thing that I didn't know about.

[steven79]

well the lower the temp the faster it will open and the less time the water will stay in the rad so it will not cool off as much, so if you put a 180 or 195 t-stat in it it will let the water sit longer in the rad and cool it off and will keep the engine at that temp.

[seadog]

OK I will try that and see whats up

[Nobby]

Seems to me that many recent posts I have read on cooling issues comment on the need for the shroud, and that it makes a marked difference.
Never ran mine without but it makes sense to me that it would improve things.

[ October 28, 2003, 09:19 PM: Message edited by: Nobby ]

[Heimeken]

a new rebuild will generally run a bit hotter, but shouldn't heat up that fast. You must have some water flow issues, maybe the t-stat is stuck or your radiator may be clogged up. Fan shroud? I don't have one here in the desert and never heat up. 4 core radiator would helps lots. Make sure your tranny isn'nt causing too much heat also, taking to the radiator.

[gwinn]

Welcome to the club! If you don't already have a shroud, install one because you'll need it next Summer. A 4-core radiator could help, but it appears to be something possibly even more serious to me. Even with some inefficiencies in your cooling system, you shouldn't be overheating on a 55* day. I kind of agree with Jaime, something is restricting your waterflow. Just how hot is your engine getting?

[Gawdzilla.]

check the radiator anyway. I had similar problems before when I thought it was ok and turns out I needed a re-core. So, new water pump and thermostat and 60 dollars later- I tried the radiator. They will sludge up within a year if you don't flush it fully.

[letank]

80/20 water... this is your problem.... you should not go over 50% coolant...... you are almost running "alcohol" which has a very low boiling point..... about 25% less than water... sorry i am a centigrade guy= 75 versus 100 for water

go to a 50/50 mix.... or even a 30/70 water..... for a test you can try 100 percent water.... with the water wetter.... of course i hope that you do not have freezing weather.....

distilled water is also better

Michel

[Retro93]

He's running an 80/20 water/anti-freeze mix, which is fine as long as it stays warm out.

Put on a fan shround, replace the tstat with a 180 degree unit. Sounds like the fan clutch is bad too...might be a good idea to replace it while you're at it. smile.gif

[andy d]

the old engine in my new 88 ran hot. when i swapped in the good engine, it too ran hot. the radiator was fine had good flow in it. i had used the original clutch fan. swapped it and now have cool runnings

[1BDWAGN]

I think the problem may be in his second post. He said that he did not burp the cooling system. That needs to be done before anything else. Just leave the cap off and allow the vehicle to reach running temperature. When you start see good water flow in the radiator and the truck is warmed up then put the cap back on. If you don't already do it I always drill a hole or two in the flange of the thermostat which helps trapped air escape too.

[Joe Guilbeau]

Originally posted by steven79:
well the lower the temp the faster it will open and the less time the water will stay in the rad so it will not cool off as much, so if you put a 180 or 195 t-stat in it it will let the water sit longer in the rad and cool it off and will keep the engine at that temp.You quite sure about that?

One might postulate that, say in the morining on first start-up, since the thermostat is indeed closed, the water in the radiator might not be as hot as the water in the block, eh?

Only when the thermostat opens will any substantial hot water enter the block, so I am confused as to why a thermostate that opens earlier or later in the temperature range will have much, if any effect upon the temperature of the water in the radiator.

I believe that a thermostat in the 180-195 degree range is the proper selection, by the way.

[89grand]

I think he was saying that with a higher degree thermostat the water would remain in the radiator longer while the engine is running, not during start up, and therfore get cooled by the fan as opposed to a 160 thermostat which is almost like running without one once the engine gets to 160 and beyond which it most certainly will. With a 160 degree thermostat once the engine is running and at 160 degrees or beyond, the thermostat would remain constantly open because the motor would never get below 160 degrees, and the water in the radiator would spend very little time in the radiator to get cooled by the fan. I think the belief is with a higher degree thermostat like 195 for instance, the thermostat would sometimes close while running giving the water in the radiator time to be cooled by the fan before it opened again letting cooler water into the engine.

In theory this makes sense. I don't know if it really works this way or not.

[Joe Guilbeau]

Originally posted by 89grand:
I think he was saying that with a higher degree thermostat the water would remain in the radiator longer while the engine is running, not during start up, and therfore get cooled by the fan as opposed to a 160 thermostat which is almost like running without one once the engine gets to 160 and beyond which it most certainly will. With a 160 degree thermostat once the engine is running and at 160 degrees or beyond, the thermostat would remain constantly open because the motor would never get below 160 degrees, and the water in the radiator would spend very little time in the radiator to get cooled by the fan. I think the belief is with a higher degree thermostat like 195 for instance, the thermostat would sometimes close while running giving the water in the radiator time to be cooled by the fan before it opened again letting cooler water into the engine.

In theory this makes sense. I don't know if it really works this way or not.I am lousy at guessing what folks mean, I can only read the info put forward and base my opinions on that. You are probably right, this may be what he meant, and if it is...well, it's not a very accurate theory.

[reddog]

I think a 195 stat will help it to be more stabil but not restrict flow. I would swap the stat (180 is my fav) and flush the system well. Also make sure that the heater is connected and if you bypass the heater core make sure to connect the block fittings so that water flows through the rear of the engine.

Kerry

[ October 29, 2003, 06:49 PM: Message edited by: reddog ]

[srpez]

I have to jump in on this one because I'm really confused on the theories being put forward here. The T-stat isn't keeping water in the radiator to cool longer, it's keeping it in the block until reaching the temp rating then opening the flow to the radiator... so when temp hits 160 on a 160 degree T-stat flow starts heading through the radiator to cool the fluid and maintain a 160 temperature...I think! Anyway, I can only back this up by having changed my thermostat this weekend with a 160 degree one from a 180. My temp was holding at mid gauge, now it just gets above 1/4 of the way. Can't argue with results!

[Don S]

..
srpez;

... The flow configuration for the coolant is that the water pump pressurizes the block. The head distributes coolant though the cavities into the block. Block pressure must be consistent from front to rear to insure uniform coolant distribution and to reduce water pump cavitation.
... Less pressure will results in less flow around the rear cylinders. When we boil this fact down it simply means the thermostat is a useful tool in maintaining the pressure and to maintain the proper amount of heat.

... Unless there is a malfunction of the thermostat a thermostat with a lower temperature rating will not normally help the engine to run cooler. Cooler than normal thermostats reduce the ability of the engine to expel water vapor from the engine oil.

Good Luck.. http://www.boylover.net/ubb/graemlins/cool_shades.gifand CUL.. Don S..

[Gawdzilla.]

OK Seadog, who gets the biscuit?

[seadog]

I get off the boat Wed. and will see whats up with this thing.I guess a brand new clutch could be bad.Havent felt my rebuilt trannny,that could be overheating.The radiator was fine a few months ago when I took it out.Anyway I have some good ideas to check out now that I didn't think of.

[seadog]

Ended up being the new fan clutch was faulty in conjunction with having some air in there also.