[IDMiller]

Ok got something odd happening but dunno what to do or what it means. The outside temp has been rising but I've had other 80-90 deg days since this and not had a problem.

This is an 86 with a 305 new water pump, roughly 50/50 mix new thermo * high performance 160 deg. has huge opening. radiator and engine block have been tested for for leaks and clogs both hold up well. up until recently it's been hovering the 180-200 range and the 200 range is generally running around stoping here stoping there over and over. should this be happening?

I don't have any coolant on the dipstick after it's been sitting or after running. no oil floating in the coolant.

no white smoke coming out the back. either while getting on it or tenderly loving it.

I'm discombobulated as to what it is.

 

[Zerberfert]

Why are you running a 50/50 mix? I think it runs cooler on a 100% antifreeze. As long as it doesn't go over 220 or so, you should be good. Lots of hot rodders and NASCAR run their engines at higher temps.

 

[bige]

50/50 is proper. Water actually cools better than Anti Freeze but has no anti-corrosion protection and 100% anti-freeze turns into a slushy type semi liquid at freezing and below.

I just went through a similar issue with mine and it was the fan clutch. Actually cooled fine at low speeds and ran hotter at 70 mph and above. Replaced it with an hd unit and dropped 20 degrees. Managed to drop it another 10 with a 7 blade fan but the noise was too annoying.

ErnieR

 

[fauxrs]

Why are you running a 50/50 mix? I think it runs cooler on a 100% antifreeze. As long as it doesn't go over 220 or so, you should be good. Lots of hot rodders and NASCAR run their engines at higher temps.

A car will NOT run cooler on 100% antifreeze, the most efficient is 100% water, but that has its own issues with no corrosion protection or any lubricant for the water pump. 50/50 is the reccomended mix, however you could go to 25% AF with water. Remember its called anti-freeze and that is the function it performs, calling it coolant is an oxymoron as it is lousy as a heat transfer medium compared to water.

You say up until recently it has been running at 180-200...whats it running at now?

What you are seeing may be the actual cooling capacity of your system, if the lowest temp it can hold is 180 degrees then that really represents the best cooling capacity of your present system. You can make some minor improvements by ensuring the face of the radiator is sealed to the core support. You want to eliminate any air rushing around the rad as opposed to through the rad.

Similarly the shroud should also sit tight to the face of the radiator, if you are running a factory clutch fan you want to ensure its working properly. An auxilliary electric fan can be fitted for traffic situations when using a clutch fan.

Your engine is almost certainly designed to operate in the 200-220 region for emissions purposes these are not uncommon temps, nor should they be a worry to anyone with an emissions motor.

 

[SINISTER]

Coolant flow through each engine is different.
Where is your sending unit mounted?
It's not uncommon for one section of the motor,(front) to be cooler than the rear.
The front receives better flow and cooled antifreeze compared to the rear cylinders.
If your not spitting antifreeze,I wouldn't worry about it if your gauge is accurate.
If we could get actual temps from different motor parts,I bet they are 300 degrees or more.
The engine should run good as heat= horsepower.:nanawrench:

 

[IDMiller]

I had 100% water in it as I was trying to figure out what in the devil was wrong with the cooling systemt o begin with. My bad luck was 3 thermostats in a row. *thus the new water pump it was 22$ so I said wth why not*.

How would I test the fan clutch.

I agree anti-freeze isn't really coolant but the general masses use the terms interchangeably which could be another argument altogether.

now it's running 220ish maybe a little over the top of 220 which i'll give 225. I have taken the time to ohm the sensor and verify with the meter AND IR thermo at the reading site that the gauge in the dash is accurate. *had alot of trust isses with the work a previous mechanic did to it* it reads and measures with-in 6 degrees. and for an analog gauge i'm ok with that.

now does heat really=more hp? becase maybe i can get my money back for the performance part. surely with that moto i would be better off with the 195.

if it cools better at highway speeds than at lower speeds what is that a sign of? I havn't really had it on the highway as of late.

thanks for the ideas

 

[fauxrs]

I had 100% water in it as I was trying to figure out what in the devil was wrong with the cooling systemt o begin with. My bad luck was 3 thermostats in a row. *thus the new water pump it was 22$ so I said wth why not*.

How would I test the fan clutch.

I agree anti-freeze isn't really coolant but the general masses use the terms interchangeably which could be another argument altogether.

now it's running 220ish maybe a little over the top of 220 which i'll give 225. I have taken the time to ohm the sensor and verify with the meter AND IR thermo at the reading site that the gauge in the dash is accurate. *had alot of trust isses with the work a previous mechanic did to it* it reads and measures with-in 6 degrees. and for an analog gauge i'm ok with that.

now does heat really=more hp? becase maybe i can get my money back for the performance part. surely with that moto i would be better off with the 195.

if it cools better at highway speeds than at lower speeds what is that a sign of? I havn't really had it on the highway as of late.

thanks for the ideas

If it cools better at highway speeds than traffic speeds then its a fan issue, i.e. the fan cannot pull enough air through the radiator to cool the motor effectivly at low speeds. This is why sometimes an auxillary fan is effective.

Technicly yes, an engine is really little more than a heat pump, however a cooler intake charge makes more power than a hotter intake charge, so high underhood temps can kill power because it heats the intake charge, this is why cold air intakes make power.

 

[SINISTER]

You could try a 180 thermostat,as you don't want the coolant passing quickly through the engine either.
It needs some time to transfer the heat to the radiator.
Is your heater core hooked up?
The additional coolant capacity and smoother flow may settle the system down.
Are you using distilled water?
Tap water has impurities that can cause problems.
Look into the radiator and look for deposits,you my want to flush the system with prestone super flush and refill with green antifreeze and distilled water.
Don't buy the orange, red, or other crapola.
Heat=horsepower,the engine always runs best right at the point of destruction.

 

[Skandolis]

just my two cents, but a 50/50 coolant mix will run 10 degrees or so cooler than straight water(antifreeze does help cool as well)you might try some of the addidtives, oreillys has one called water wetter thich will give you a few more degrees cooler.stock a 86 305 should be running a 180 degree thermostat.heat does not mean horesepower, heat is a side effect. horsepower comes from cold fuel and cold air being combusted(the colder the fuel the more power )higher temps do mean less sludge and buildup in your engine on the other hand 220 degrees don't seem dangerous, but does seem hot for a 305 with 160 stat(modern 6 cyl are designed to run around 210, old v8s not so much)but personally i like my ole 350 to run around 175(which it does with a 160 stat)if it's heating now, get it taken care of, summer months this year is gonna be blistering. a radiater flush would be one of the places to start.(you said this rise in temp is recent, have you changed the timing?)

 

[SINISTER]

Smokey Yunick has the following to say about coolant flow:

I believe the standard coolant flow in a smallblock Chevy is simply not adequate for an engine that develops more than 500 horsepower...a coolant flow of at least 100 gallons per minute is required to maintain a suitable thermodynamic balance in the engine.
I don't think it is possible to gain these flow levels with a stock water pump and a conventional flow pattern...I have never tested any stock or specialty Chevrolet water pump that can push more than 68 gpm through the stock block and heads! And I don't care what you do to the pump, it's not going to get any better with a stock flow system. The biggest trouble, of course, is air cavitation...when the shaft speed exceeds the point where the stock-type pump puts out about 68 gpm through the system, the pump starts pushing air into the engine along with coolant, and this greatly reduces the heat carrying capacity of the coolant.
Running an engine at 180° will drop the overall horsepower by 2-3%. For max power the coolant should be at least 200°, and you should have at least 25 pounds of pressure in the system. Actually a racing engine like the smallblock Chevy will produce more horsepower as the operating temperature is increased, all the way to a maximum limit of about 220°.

Smokey Yunick's Power Secrets - Page 118-120

 

[80v6]

Coolant temp.

I have read a couple articles on optimal engine temperatures. Tests show 180 degrees is just hot enough to burn off contaminates in the oil. 165 degrees is too low and 195 is acceptable but doesnt quite create the optimal heat range for air/fuel mixture, power wise and breaks down the oil faster than 180. Very simple explanation but it seemed logical to me. Doesnt pertain to synthetics.

 

[Matrixx]

You never said wether this is completely stock with computer controlled carb and distributor.
If it is bone stock the stock thermostat is 195 to allow it to go into closed loop for emissions.

 

[ccc]

most likely cause is the setting on your fan clutch.check to see that the coil in the front of it isnt clogged with dirt and dust. if the fan isnt pulling at 220 it is either dirty or worn. do you still get the roar when you first start in the morn.if not that is the first sign the fan clutch is getting tired. i always use the hd/severe duty fan clutches,they are what was original on our cars in the first place.stay away from the cheap ones

 

[jlcustomz]

Coolant additives may help some, but won,t fix your problem. If fan & shroud are ok & thermostat has been tested, radiator is my 2ndlargest concern. I have a copper 4 core that I noticed online advance auto is still selling. Kept my HO tpi cool, Now my ls1. I learned from my former 9,000 lb worktruck what a difference a proper radiator can make.One of the new plastic/ aluminum cheapies I last got outcooled the other replacement (high capacity) model by a ridiculous amount.

 

[Red Regal T]

You might consider going to electric fans.

 

[IDMiller]

The computer control has been removed, the dist is now an hei, and the carb changed, it's electric choke.

The timing hasn't changed but it does need to be adjusted. Just havn't had the time, or proper tool.

It had an idiot light but I changed it out for gauge cluster. I know that it works properly and the 220 is straight up center. my chevy silverado v8 5.3 runs 210-230ish pending if I'm towing but it also has a 195 degree thermostat. maybe I'm just over reacting but thats 15-35 degrees hotter than the thermo on the pick up but 40-60 degrees hotter on the elky.

It was recently flushed and cleaned out. the temp sending unit is below the spark plug on the number 1. I'll look into changing it back to a 185/195 if you all think it's better for it. it was bought in fustration to begin with.

On the note of distilled water. distilled water has a lower boiling point than tap water. it's also dangerous in a clean enviroment. *many people have mistaken distilled water and boiled it to make tea only to have the water "explode" when the bag is introduced as a containament* I'm curious as to the advantage of it.

 

[IDMiller]

something that i failed to add to the thought process.. while troubleshooting the coolant flow she managed to get a little out of control and there was at least 3 times i realized she was in the 300+ degree range. it happens so fast and when your deep in thought at the radiator you tend to get time warped. anyway something new poped up last night and i think i might have the problem solved... i'm loosing oil pressure. borderline red bar on the stock gauge. plus i'm getting little puddles of oil around the intake. i do think i've lost my head gaskets. what you think?

 

[fauxrs]

something that i failed to add to the thought process.. while troubleshooting the coolant flow she managed to get a little out of control and there was at least 3 times i realized she was in the 300+ degree range. it happens so fast and when your deep in thought at the radiator you tend to get time warped. anyway something new poped up last night and i think i might have the problem solved... i'm loosing oil pressure. borderline red bar on the stock gauge. plus i'm getting little puddles of oil around the intake. i do think i've lost my head gaskets. what you think?

Doubt it. there are no pressurized oil passages in the head, you could in theory remove a head entirely and still maintain oil pressure (it would be messy though ). That high a temp though can do other types of damage, that might allow seepage of oil drainback from the head. There are two clues for blown head gaskets -

1. White smoke out the tailpipe, in rather large quantities, with a sweet smell - this is your water/coolant mix burning in the combustion chambers
2. bubbles/foaming in the radiator at the fill cap - this is leakage into the cooling system.

In both cases there is a marked reduction in power.

At that high a temperature the viscosity of your oil will be lowered quite alot (depending on the oil) which would account for low pressure. Oil on the intake manifold near any of the bolts is simply oil seeping up the threads of the bolt via capillary action and is resolved with a little non-hardening sealer on the threads before the bolt is installed.

If youve run temps like that a few time I would reccomend changing the oil, if the filter is fairly new you neednt replace that, the high temps wont effect it.

 

[SINISTER]

Usually over heating,when the cooling system seems to be in good condition,is engine wear related.
Low oil pressure is another symptom of worn engine components.
Excessive bearing clearance will result in low pressure readings when warm.
Elevated engine temperatures from worn parts cooks the oil,resulting in the oil being vaporized and losing the protective wedge between parts.
This results in higher temperature and more accelerated wear.
How many miles on this motor?
As a last resort you may want to try some thicker oil so see if the pressure comes up..a temporary fix at best.

 

[ccc]

a really worn engine will usually run cooler due to less friction. oil pressure will drop as clearances open up in the bearings and the oil pump itself wears. as the engine wears it gets more blowby and you will find more leaks in places not sealed correctly initally. when its hot spray the radiator with a water hose if the temp drops instantly the fan isnt pulling enough air to let the radiator do its job.if it slowly comes down you have either a radiator or internal or tune issue