Over Heating

[nsbluenose]

Acollin, you are suggesting increased pressure?

 

[howehap]

The car has not "boiled over". It runs up to about 205 F or so, so I don't believe more cooling system pressure is a corrective action.

My additional investigation has shown the following:
The mark on the pulley is within 5 degrees of TDC. ( Most likely the damper has not become unbonded?)
The valve timing appears to be close to spec, so the timing chain most likely is not off by one tooth ( RootesRacer recomended valve timing check)
Still need to pull lower radiator hose and check for delamination on inside (hose looks fairly new on outside....)
Advanced ignition timing to about 15 degrees before TDC instead of 8 degrees TDC (timing advance did not seem to bring temperature done at all, mechanical and vaccuum advance appear to be working ok)
Pressurized each cylinder to 100 psi and there was no indication of bubbles in the radiator.
Retorqued the head and re-adjusted the valves ( backed of each bolt 1 flat and then retorqued, moved about 3 flats when retorqued to 48 ft-lbs, don't know if the rebuild had used the 45 or 48 ft-lbs value)
Heater hoses get hot right away, and since the control valve is stuck in the open position, coolant is always running through the heater core.

Still waiting for owner to get back to me on what was done during restoration. I'm running out of ideas other than pull the radiator and get redone. I might pull the timing chain cover to verify valve timing at the same time.

Any other ideas?

 

[Bill Blue]

So it runs hot but has never boiled over? What do you call overheating?

Bill

 

[howehap]

It has a 160 F thermostat. RootesRacer said I should expect about 180F or so at 40 mph constant speed that I was driving at, and if I was much over that then something was wrong. So I consider 205F after a 5 to 10 mile drive, and run-on when I turn the car off to be over heating. I didn't want to keep driving to see if I could get to 220 or so and boil it over while out on the road.

 

[husky drvr]

howehap,

Is there any chance the thermostat is installed upside down?

Can you use your infrared thermometer to check how warm the oil cooler gets when the engine is trying to overheat?

A quick check to see how much of the radiator might be clogged is to run the engine till going hot, then shut down the engine and lightly spray water on the radiator cooling fins. The cooling fins that dry quickly have coolant flowing. Those areas that remain wet have no coolant flow. This isn't a really reliable test but sometimes is a good indicator for peace of mind.

 

[howehap]

I guess it is possible and I somehow put the thermostat back in backwards, distractions do happen. I will check when I drain the system and check the lower hose. My infrared thermometer didn't show much difference in temperature on the radiator, but it difficult to get a good shoot at all of the radiator through the grill. I will try the water test on the radiator and also check the oil cooler temp. What oil temp would be considered overheating?

 

[howehap]

Took the car for a 12 mile ride at 40 mph, started cold. fairly flat, 85F ambient, coolant got up to about 205 F. With infrared gun, oil cooler 160 F, thermostat housing, 205F, radiator ~185 F near outside, ~170 F in front of fan. tried spraying water on radiator after stopping engine, didn't see any big difference in evaporation in different parts of radiator.

 

[beamdream]

185 at the radiator sounds ok with 85 ambient.

Just so we're on the same page - point your laser at the radiator top hose area then at the bottom hose area and note the difference between the two readings, this should give an indication of the effectiveness of the radiator; a 15 to 20 degree drop is ideal.

Do you still have the low vacuum at idle issue ?

 

[howehap]

185 F was the shooting at the radiator fins from the front of the car. Top radiator header is 200-205F. Need to measure bottom header. When I did the top and bottom hose last week, I wasn't getting consistent readings, sometimes readings were almost the same, sometimes 15 F different. Need to try again, I was thinking the fan might have been cooling the rubber surface and affecting my readings

 

[beamdream]

185 F was the shooting at the radiator fins from the front of the car. Top radiator header is 200-205F. Need to measure bottom header. When I did the top and bottom hose last week, I wasn't getting consistent readings, sometimes readings were almost the same, sometimes 15 F different. Need to try again, I was thinking the fan might have been cooling the rubber surface and affecting my readings

Ok, top header at 205 is concerning, interested to see the bottom tank temp; what about the vacuum issue ?

 

[husky drvr]

Took the car for a 12 mile ride at 40 mph, started cold. fairly flat, 85F ambient, coolant got up to about 205 F. With infrared gun, oil cooler 160 F, thermostat housing, 205F, radiator ~185 F near outside, ~170 F in front of fan. tried spraying water on radiator after stopping engine, didn't see any big difference in evaporation in different parts of radiator.

howehap,

The oil cooler temp seems to be a bit low, but my only reference is like comparing apples to watermelons. A different member built a really nice turbo Rootes engine and installed a temp sensor in the cooler adapter. I recall in one of his posts that he was showing 180* after the cooler. The cooler helps but even if not working, shouldn't cause all of your issue. Your water test sounds like your radiator is most likely in decent working order. Your radiator temps ( 35* change from housing temp) would seem to agree. If you are actually having a 35* or greater temp change as measured at upper tank inlet to lower tank outlet, I think your weak link is something else.

To restate your issue as it sounds to me, your radiator, thermostat, and water pump seem to function normally but for some reason coolant flow is restricted somehow so the head is not cooling correctly even though you have cooled coolant going into the bottom of the engine. If the pump works and radiator works, what is causing the flow imbalance?

You might need to install a restriction in your heater hose circuit to slow flow through the heater since you don't have a control valve.

Is there any chance the bypass hose between thermostat housing and water pump is not installed?

Hopefully some small part of this will help,

Don

 

[howehap]

Results of additional testing. Started car up cold, ambient in garage is 85 F. Took 15-20 minutes to get up to 200F. Looks like ok flow of coolant at 1500-2000rpm. Slow flow at 1000rpm idle.

• 1000rpm, vac 15 inches, thermostat housing 176F, upper radiator header 176F, lower radiator header 173F
• 1500rpm, vac 17 inches, thermostat housing 188F, upper radiator header 184F, lower radiator header 184F
  
• 2000rpm, vac 18 inches, thermostat housing 200F, upper radiator header 200F, lower radiator header 197F

There doesn't seem to be any delta T across the radiator...hmmm. The vaccuum seems low too, for a second ...hmmm.
I haven't verified that I don't have the thermostat in backwards yet and look at inside of radiator hoses, need to let it cool down. Yes, the heater control valve in in place, it's just stuck in the open position. Looks like all the coolant lines and by pass is correct, I can send photos if anybody cares.

So comments and suggestions?

 

[RootesRooter]

Anyone in your area you could borrow a radiator from for comparison? Before that, just for sh*ts and giggles, put in a different thermostat - and go hotter.

 

[howehap]

I have a few other alpine radiators hanging around, but don't know their condition. I think I have a working 180 F Alpine thermostat too. What's the thinking on the 180F thermostat, engineering curiosity?

 

[Gordon Holsinger]

I have a few other alpine radiators hanging around, but don't know their condition. I think I have a working 180 F Alpine thermostat too. What's the thinking on the 180F thermostat, engineering curiosity?

I have run a 160 thermostat in the summer. If I remember there were some aluminum water pumps a few years ago if you have one I mite be inclined to pull it and look if it is corroded internally and diminishing the flow. I assume you are running premium fuel.

 

[husky drvr]

Results of additional testing. Started car up cold, ambient in garage is 85 F. Took 15-20 minutes to get up to 200F. Looks like ok flow of coolant at 1500-2000rpm. Slow flow at 1000rpm idle.

• 1000rpm, vac 15 inches, thermostat housing 176F, upper radiator header 176F, lower radiator header 173F
• 1500rpm, vac 17 inches, thermostat housing 188F, upper radiator header 184F, lower radiator header 184F
  
• 2000rpm, vac 18 inches, thermostat housing 200F, upper radiator header 200F, lower radiator header 197F

There doesn't seem to be any delta T across the radiator...hmmm. The vaccuum seems low too, for a second ...hmmm.
I haven't verified that I don't have the thermostat in backwards yet and look at inside of radiator hoses, need to let it cool down. Yes, the heater control valve in in place, it's just stuck in the open position. Looks like all the coolant lines and by pass is correct, I can send photos if anybody cares.

So comments and suggestions?

No delta T through the radiator is either no air flow through the radiator or the radiator has been painted in such a manner that the paint either blocks airflow, insulates the air contact surfaces, or both. I'm presuming you don't have an AC condenser in front of the radiator. Try shining a flashlight through the radiator core and see how much light you see. You might want to compare the same test on a different Alpine radiator. You might need an extra hand.

The WSM 145 recommended thermostat is 180* for alloy head engines.

Try rechecking your vacuum readings with the PCV hose disconnected and plugged at the valve. It almost sounds like the PCV isn't working or is working in a reverse manner due to having the incorrect PCV installed.

 

[Gordon Holsinger]

Looking for things to check on stock Alpine series V that seems to run hot. Rebuilt engine, radiator cleaned (I don't know what was actually done to the engine and cooling system, I need to find out from the owner). Guessing around 100 miles on rebuild, just short runs of less than 10 miles.

• 80 F ambient, coolant temp goes to around 210 F before I shut it down.
• Same temperature rise at idle and on road at around 40 mph
• Measured with thermometer in radiator and infrared gun below temp sending unit, and instrument gage, all show around 205-210 F.
• 160 F thermostat, taken out and checked in boiling water, it's ok
• good flow in radiator
• coolant 50/50
• when hot, it will diesel when I shut it off.
• Ignition timing 8 degrees BTDC (@ 800-900 rpm). Centrifugal and vacuum advance seem to be working ok when checked with timing light.
• Manifold vacuum seems low, 900 rpm = 15 to 16 inches: 2000rpm = 20 inches
• don't see bubbles in radiator coolant

I wish you lived closer I’m on the east coast. Everyone seems to have covered the common overheating issues. I have a stupid question is the fan on the rite way? Pulling air through the radiator. Many years ago my college classmate had an overheating problem on his MG he had replaced his water pump and put he fan on backwards!

 

[bernd_st]

First and most important check would be whether your cooling system holds the pressure. Check all antifreeze plugs and the heater if installed. If everything right and pressure proof get the radiator a good rebuild. The original Rootes core was rather underspec'd and things get worse when getting clogged and aged . Cleaning is not enough ! If still no cure pull the rearmost antifreeze plug on the block driver side and give it good flush with a hose. A cut wire coat hanger helps to get all the grime ,rust and deposits out...

 

[Bill Blue]

It is hard to see how lack of cooling across the radiator can be due to anything besides air flow. If the radiator was plugged internally, the bottom header would be cool, but the flow rate would be too low to cool the car. If the problem was fan or fan speed speed, it would go away at speeds over 30 mph. To me, this means something is inhibiting air flow through the radiator.

Bill

 

[howehap]

The fan is moving plenty of air, and yes it is pulling it through the radiator in correct direction. I compared the radiator to my 2 non-running Alpines, they all look the same, I can shine a light through all of them, fins are wide open. The problem child radiator has been painted, but it looks thin, like what I would expect from a radiator shop. I'm still waiting to find out from owner if anything was done to the radiator.
I could see where a blocked passages in the block could lead to steam and boil over (local on spot), but I struggle to see how blocked passages would directly lead to the high temperatures that I see, but don't lead to boil over (so far).
I removed, disassembled, and cleaned the PVC valve. It seems ok. When I put my finger over the hose going to the PVC, the vac only increase by about 1 inch. I believe it is stock.