Running Hot on the Highway

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How far is the fan into the shroud?.If the blade is to far in or out it will run hot down going the road.
Jim
 
Don,t overlook the radiator. Just because it is new doesn,t guarantee free flow. I had a a similar problem with a BeCool that I replaced everything before checking the rad.
 
My concern at this point is the upper hose and radiator are not hot, just warm, but the intake manifold below the thermostat housing will burn your hand. The thermostat is not letting the coolant get to the radiator. Next step is to put a new 180 in there and see what happens.
 
340sFastback said:
My concern at this point is the upper hose and radiator are not hot, just warm, but the intake manifold below the thermostat housing will burn your hand. The thermostat is not letting the coolant get to the radiator. Next step is to put a new 180 in there and see what happens.
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Now your talking!The 160 thermo is letting 160 degree water in and closing,thats why,,hot engine cool rad to fast.The 180 thermo will fix!
 
In your original post you mention that the engine has 500 miles on it so far. Has the overheat issue been there since day 1? If so, here's a few thoughts as I just went through a strange overheat situation at work.

First of all, did you properly bled the cooling system when you filled it? An air pocket will give you issues.

If the condition has been there since you first installed the engine maybe there's a head gasket problem, such as blocked water passages?

Manually test the thermostat operation with boiling water? I've had plenty of bad "new" thermostats over the years.


Was the engine a core from an unknown source, or was it your engine that you were familar with? The reason I ask is because just last week at work a 2005 FX-35 came in overheating after the owners friend installed a new thermostat to correct the overheating. I pressure bled the cooling system and it would idle all day at 185. Get on the highway and within a mile it would overheat. I installed a new thermostat and radiator: same thing. We tested the coolant while it was running with the exhaust gas analyzer we use for state inspections; no HC or CO, which pretty much ruled out a head gasket, plus the oil was clean, not contaminated with water. Coincidentally, while this vehicle was in the shop a factory troubleshooter was in the store for a different problem car and my manager mentioned the problem to him. His response was replace the engine! It seems the `05 Infiniti 3.5 had random issues with the water jackets scaling up with corrosion and it acted as a thermal barrier not allowing the heat to transfer to the coolant. Sure enough I dropped in a long block and the sunofabitch runs cool at highway speeds. I drove it home last night and put about 50 miles on it, of course with the customers permission.

Sure hope that isn't the issue with your car, but I mention it as a rather extreme example of something that could drive you crazy. Granted, the Infiniti is an aluminum engine and electrolisis happens, but not like this one, and if the block is an unknown, it might be the problem. Try the suggestions mentioned already before you open it up. :-|

Good luck!
 
OK can I ask a dumb question. From the pictures of the water pumps, unless there is reverse image, it looks like a driver side lower hose. Is that right? If that is the case, then are the belts driving the water pump the correct way?
 
3406pk said:
OK can I ask a dumb question. From the pictures of the water pumps, unless there is reverse image, it looks like a driver side lower hose. Is that right? If that is the case, then are the belts driving the water pump the correct way?
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It's not a reversed image as the decals all read correctly. I'm still wondering the same thing, but tonight I'm having trouble thinking in three dimensions enough to visualize coolant flow through the impeller.
 
if it only gets hot at higher rpms the water is cerculating to fast wich would tell me term,stat is bad i know ive had bad new ones.and i agree 200 is to hot. stant or napa 165 or 180 for me
 
also if you think hose is sucking shut if you rev motor you should see it sucking. if so put a hose clamp over area litely titen and trit if so it is the hose. i would try that first.if hose is old and flemsy very posable.
 
I know allot of people have a problem understanding the function of the water pump. it is a centrifugal pump, water enters the "eye" or center of the pump and is forced outward. This is why if you look at the picture of the pump you will notice the lower radiator hose connection, the entrance for the water is behind the impeller. As the Wp pulley is spinning it actually creates a negative pressure below atmospheric level which is 14.7 at sea level which tends to move water from a higher pressure to a lower pressure at the eye of the impeller and thus the impeller moves the water away from the eye and throws it outward thus causing water flow thru the system. The faster it spins the more circulates. The plate on the back of the impeller on the new pump is there to ad a "back wall" to the impeller to make it more efficient.
 
For sure the first thing I would do is ditch the 160 stat for a 180. also if your lower hose is sucking shut then you know you have a flow problem. the hose sucking shut tells you the pump is pushing the volume of coolant passed the stat, through the radiator but the radiator can't supply it back fast enough so it builds pressure in the upper hose and sucks shut the lower. In alot of cases the high flow stats are not necessary and can prove to be more of a problem.
 
A lot of good suggestions above, thanks for all who contributed. I am going to try a new 180 thermostat next because it appears the Mr Gasket 160 High Flow is not letting the coolant circulate correctly. We have rain for the next few days so it will probably be a while before I get the car back out.

The lower hose on the water pump is on the driver's side. All '69 and earlier small blocks had that configuration. In '70 they switched to the pass side.
 
BTW: What does this Mr. Gasket high flow thermostat look like? Does it have 3 holes around the perimeter of the block-off? I had one of those once and it NEVER opened at highway speeds.

Install the stock-type 180 degree and be done with it....
 
Use Milodon Thermostats. Never had a bad one yet. They are all brass and high flow as well, they open WITH the flow of water, unlike stants.
 
....I guess I'll jump in and beat a dead horse...:-D From what I know, the fan and shroud should be meaningless @ highway speed. You either don't have enough coolant flow, not enough air flow or not enough core area in that radiator for your hopped engine/trans combo.....which is what I suspect. Remember, those temps you stated still aren't even boiling yet.....but yeah, I'd want mine cooler than that too.

I once had an A-100 pickup with a built 340 in it.....and had a helluva time keeping it cool. It was kind of the same situation as yours......when I got up to freeway speeds, the coolant temp would just creep up to about 210~215. But I know my problem was air flow......there was almost none. I slapped on a large engine oil cooler with it's own little shroud to blast air through it and dropped a good 15~25 degrees from the coolant temp.
 
Here is the Mr Gasket high flow. I drilled three 1/8" holes in it prior to installing to prevent air pockets. I threw it in a pot of boiling water today and it seems to opens nice and wide. But like I said before, intake manifold below the thermostat would burn you fingers while upper hose and radiator were just warm. For some reason coolant is not flowing past the thermostat.

ThermostatTop.jpg


ThermostatBottom.jpg
 
340sFastback said:
Steve, is this the one you recommend:

http://store.summitracing.com/partdetail.asp?part=MIL-16406&autoview=sku

I think I'll give it a try.
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Yea that's the one and you'll find the Milodon and Mr. Gasket look alike cuss I think they're made by the same company. Also drilling the ring is a good idea but you really only need 2 small holes to get the air out. Also when you tested the old thermo did you find that it was open about 1/4 to 3/8 of an inch. I had a Milodon high flow that right out of the case would only open 1/8" thankfully I had bought 2.

Terry
 
I now have a new Milodon 180 high flow thermostat in there and a new reproduction 16 pound cap I got from Mega Parts. The hoses are pumped up hard when the engine is hot. Engine hot I watched the hoses with revs at highway speeds and nothing is collapsing. The engine seems to really like the extra heat of the 180 thermostat. It really runs a lot better then before. I think those aluminum heads like heat. Have not had time to take it on the highway yet but it hauls *** on the back roads.

I ordered one of these today:

http://www.amazon.com/dp/B000TM7HXC/?tag=joeychgo-20

I am going to measure things with the infrared gun when it gets in and see what the temperature is of the hoses, intake manifold, thermostat housing, radiator etc. Then I will have a better idea what is really going on.
 
340sFastback said:
I now have a new Milodon 180 high flow thermostat in there and a new reproduction 16 pound cap I got from Mega Parts. The hoses are pumped up hard when the engine is hot. Engine hot I watched the hoses with revs at highway speeds and nothing is collapsing. The engine seems to really like the extra heat of the 180 thermostat. It really runs a lot better then before. I think those aluminum heads like heat. Have not had time to take it on the highway yet but it hauls *** on the back roads.

I ordered one of these today:

http://www.amazon.com/Mastercool-522...pr_product_top

I am going to measure things with the infrared gun when it gets in and see what the temperature is of the hoses, intake manifold, thermostat housing, radiator etc. Then I will have a better idea what is really going on.
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Glad you,ve found your problem.After installing my engine/tranny and all the other goodies that go with 6/360 conv. in a 66 Dart,I found out there,s a pin hole in driverside head and ofcourse it,s in the rear.Good Luck and keep it cool!
 
Petty, while things look good so far I have not ran it on the highway yet. I will probably wait until the I get the infrared gun then I will do some more testing.
 
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