Engine running hot

[Lakeway Cobra]

Looking for a bit of advice on a somewhat hot motor.

Running a 185 degree thermostat and it has a pair of 1/8" holes in it to help self bleed air. Engine ramps up to 200 pretty quick and fan kicks on to keep it at that level. some questions....

1) I'm thinking air in the system. What are you guy's doing to bleed air out of the cooling system? I've tried the nose up method and it didn't seem to help much.

2) Also what is your cold water level with this radiator setup (or will that vary too much motor to motor to have a common benchmark).

3) Do I really need a shroud? And does it matter if it is a front or rear shroud?

Thanks.

[Barnsnake]

In no particular order:

Coolant level - The engine and radiator should be all coolant and no air. In addition, there should be something left in the recovery tank when cold.

Zooms to 200 and then fan regulates - Your engine is likely making a lot of heat (that's its job, afterall) and at a standstill there is virtually no cooling sysem until the fan kicks in. It will likely cycle on the fan temperature when stationary. When moving, especially at this time of year, it should cycle on the thermostat temperature.

Air in the system - I don't remember which engine you have, so I don't know if the top of your engine cooling system is above the radiator cap, but it probably is. If you have a small block (289-302/Windsor) you can pull one of the plugs or senders out of the top of the intake to "burp" the system. The slope trick and a properly functioning recovery tank should also do it after a while. In any case, you will never get proper temperature readings or regulation with air in the system.

What is the real temperature? - You noted you have a 185 degree thermostat, but what is your fan trigger temperature? You also mentioned it goes to 200 degrees, but does it really? It's entirely possible that when your gauge reads 200 the temperature may be something else, like 185. My temperature gauge is slightly "alarmist". Buy or borrow a thermometer and determine the actual temperature. You really need to determine this so you don't go crazy trying to "fix" a problem that doesn't exist.

Keep us posted,
Jim

[Lakeway Cobra]

Thanks Jim.

Fan switch is 195 on 175 off. I think my guage reads 200 when 195 is hit.

Motor is 351W and the thermostat housing is a 45degree.

Also, my recovery tank is more of a puke tank only. It does not have the capability to allow coolant to be drawn back into the radiator.

[Bwana Snake]

Randy,

I’m running a 351W with a 165 high performance thermostat and 195/175 switch and I hardly ever get over 185 but I have both front and back shrouds, I will hit 195/200 in town in August on really hot days.

Gary

[Reptyl]

Randy,

1) I also have had issues with air in the system on my car. I bought a Mytivac cooling system Airevac kit which pulls a vacuum on the cooling system before filling it with coolant. It works okay, but is a little cumbersome to use.

2) As far as checking the coolant level when cold, my car always appears to be low, but I think the tilt on the radiator may have something to do with that. When I fill it all the way up when cold, it just pukes out the excess water when it gets warmed up and settles back to the previous level.

3) When you asked about shrouds, I assume you're talking about the shroud in the nose of the car in front of the radiator. I have one on my car and think its a good idea. I also made one that closes off the area from the hood opening to the top of the radiator, but I added it for looks rather than any cooling system benefits. I think you would benefit more from the nose shroud

RT

[Barnsnake]

With part of the engine cooling system above the top of the radiator you must run a recovery tank. Otherwise you will progressively pump the coolant out of the system until the coolant no longer reaches the radiator cap. At that point you will have lots of air in the system, especially where the thermostat and temperature sender are located.

You may be able to put the overflow connection into the bottom of your "puke tank" or install a dip tube inside it.

Jim

[Lakeway Cobra]

Thanks guys. Good info. I bled it some today from the thermostat fitting and it seems a little better. I think I'd have problems if it was 90+ degrees though.

Will try to build a radiator shroud with the Home Depot/Lowes sheet aluminum. I know some have done this so any hints, templates, pictures appreciate.

[427HISS]

If the system checks out to be in snuff, having a shroud helps tremendously. Mine went from 215 in the summer heat, down to 200. If you don't want to buy one, get like a Spal, combination shroud, fan and temp probe, they work great.

Besides that, there is nothing wrong with having a temp of 200, unless it's a modern engine with a computer.
Most cobra owners are old school so, don't worry until it's over 220. Also remember, performance engines build heat and, actually need it. You'll have more problems if it's running cold.

[Lakeway Cobra]

Update....
I ended up buying a burp funnel made by Lilse.

http://www.amazon.com/Lisle-24610-Spill ... 346&sr=1-1

First cyle this morning and I could not believe how much more air came out of the system. Just let it run with some water in the funnel and it continued to burp air out (this was after all of the other bleed methods). I will let it cool, then run one more cycle and button it up. Seems to run cooler already.

[427HISS]

I use a similar too and most automotive shops as well. Let the engine cool down then recheck the level again.

[LS 238]

One thing that helps my car is the fan is wired to a switch on my dash and I control when it comes on. Mostly I start the car let it warm up for a few minutes then turn on the switch, I have had no problems and the car runs no hotter than 180-190. But at night when I turn on the headlights my temp gauge goes up to 210. I have heard through the grapevine its a size wiring problem. Oh well just something to keep me busy in the garage.

[Lakeway Cobra]

Update.

Drove the car yesterday and it stayed at 180. Fan did not even come on after sitting still in traffic.
That's one thing off the "sorting" checklist!

[CowtownCobra]

Depends on on what you consider "hot". Everything I've seen described here is "warm" by todays standards.