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Author Topic:   overheating problems
erl
Journeyman

Posts: 8
From: Albuquerque, New Mexico U.S.A.
Registered: Aug 2004

posted 08-21-2004 03:11 PM     Click Here to See the Profile for erl   Click Here to Email erl     Edit/Delete Message   Reply w/Quote

Hello everyone. This is my first time at these forum type things. Don't know where else to get advise. Have a 74 Mustang II Fastback with a 2.8 V6. I've done everything I could do to find my overheating problem and solve it. Changed the thermostat to a 190 (thinking about taking it out altogether) re-rodded the radiator, changed the water pump, changed the temperature sending unit. The car still overheats. At least the temp. gauge says so. (haven't changed it, but will probably do that also if I can find one) What else could it be? I don't see any pinched hoses. I don't see any water in the oil (head gasket) Funny thing is that I will be test driving it after replacing one of the parts I mentioned, and if I put it in 3rd and drive in it's normal operating rpm or speed the temperature goes down a bit. I am perplexed?!! Any help on further things I could do would be helpful. erl

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SteveLaRiviere
Administrator

Posts: 44921
From: Saco, Maine
Registered: May 99

posted 08-21-2004 04:57 PM     Click Here to See the Profile for SteveLaRiviere   Click Here to Email SteveLaRiviere     Edit/Delete Message   Reply w/Quote
Welcome to M&M.

First of all, you went the wrong way on the thermostat with the 190. Although thermostats don't ultimately effect the running temp of an engine very much, the 190 thermostat stays closed until the fluid gets to 190 and since temperature has a momentum {I remember that from one of the engineering classes I took}, the 190 thermostat works against you. A 160 thermostat will open sooner and make it harder for the engine to build up heat and give you overheating problems.

Resist the urge to not use a thermostat, that's a mistake. The coolant runs through the engine too fast without a thermostat and doesn't asborb enough of the engine heat. Your coolant will run a little cooler but your engine itself will not be cooled as effectively.

Some suggestions to improve cooling:

Make sure the spring in the lower radiator hose is still there. If not, suction can actually suck the hose flat at higher rpms.

Get some Prestone Flush and flush out your cooling system. That stuff works great and you'll be able to see the difference in the radiator tanks.

Make sure you are using the right coolant ratio. You should have about 40% coolant, 60% water. {preferably distilled water} Too much coolant actually makes your engine run hotter.

Make sure your radiator shroud is there, and if you have a clutch fan it is working correctly.

Have your cooling system pressure tested and checked for the presence of exhaust gas. That will rule out head gasket and intake gasket leakage.

Hope this helps, and good luck.

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'70 Mustang Mach 1 351C 4V/FMX/3.25 Open
'70 Mustang Convertible 250 I6/3 speed/2.79 Open
'72 Mustang Sprint Hardtop 351C 4V/FMX/4.30 Trac Loc
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erl
Journeyman

Posts: 8
From: Albuquerque, New Mexico U.S.A.
Registered: Aug 2004

posted 08-22-2004 12:14 AM     Click Here to See the Profile for erl   Click Here to Email erl     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by SteveLaRiviere:
Welcome to M&M.

First of all, you went the wrong way on the thermostat with the 190. Although thermostats don't ultimately effect the running temp of an engine very much, the 190 thermostat stays closed until the fluid gets to 190 and since temperature has a momentum {I remember that from one of the engineering classes I took}, the 190 thermostat works against you. A 160 thermostat will open sooner and make it harder for the engine to build up heat and give you overheating problems.

Resist the urge to not use a thermostat, that's a mistake. The coolant runs through the engine too fast without a thermostat and doesn't asborb enough of the engine heat. Your coolant will run a little cooler but your engine itself will not be cooled as effectively.

Some suggestions to improve cooling:

Make sure the spring in the lower radiator hose is still there. If not, suction can actually suck the hose flat at higher rpms.

Get some Prestone Flush and flush out your cooling system. That stuff works great and you'll be able to see the difference in the radiator tanks.

Make sure you are using the right coolant ratio. You should have about 40% coolant, 60% water. {preferably distilled water} Too much coolant actually makes your engine run hotter.

Make sure your radiator shroud is there, and if you have a clutch fan it is working correctly.

Have your cooling system pressure tested and checked for the presence of exhaust gas. That will rule out head gasket and intake gasket leakage.

Hope this helps, and good luck.


Hello, Yeah I did have a 160 thermostat in it. It still got hot. Someone told me to put the factory temp one in it, it could be a 180. The fan is the factory fixed 5 blade flex fan. The lower hose dosn't have a spring that I can feel, though it is a thick gates hose. I will change it to a spring type and see if that helps, though it is overheating if I run it at idle in the driveway. I am running flush through it now, though it may take a few days of running it, then shutting it down before it gets too hot. I probably need to take it in to a shop to test for a head leak. Is this a common problem on these V6's ? and does it effect the coolant temperature that dramaticly? That might be my problem if I have tried everything else. I did get distilled water as I run that always with antifreeze in all my cars. Thanks for the reply.

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Percy Hazel
Journeyman

Posts: 58
From: Bellingham, WA, USA
Registered: Jul 2000

posted 08-22-2004 03:27 AM     Click Here to See the Profile for Percy Hazel   Click Here to Email Percy Hazel     Edit/Delete Message   Reply w/Quote
The V6 heads are a real weak link in the engine. That is why World Prod. tooled up and make new heads for them.
When you take it to a shop to check for a bad head they can also give you a true temp. reading.
They will probably do a leak down test. That way they will not only be able to tell you if you have a bad head but can pin point the cylinder.
Don't get discouraged.

Later

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perce111
78T-Top...IAM TOO

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erl
Journeyman

Posts: 8
From: Albuquerque, New Mexico U.S.A.
Registered: Aug 2004

posted 08-22-2004 09:58 AM     Click Here to See the Profile for erl   Click Here to Email erl     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by Percy Hazel:
The V6 heads are a real weak link in the engine. That is why World Prod. tooled up and make new heads for them.
When you take it to a shop to check for a bad head they can also give you a true temp. reading.
They will probably do a leak down test. That way they will not only be able to tell you if you have a bad head but can pin point the cylinder.
Don't get discouraged.

Later


Do these heads have a tendency to crack? So it wouldn't be just the gasket? Where would I get these World Prod. heads? Are they availible at any parts store? Thanks for the reply

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Percy Hazel
Journeyman

Posts: 58
From: Bellingham, WA, USA
Registered: Jul 2000

posted 08-27-2004 01:39 AM     Click Here to See the Profile for Percy Hazel   Click Here to Email Percy Hazel     Edit/Delete Message   Reply w/Quote
Yes they have a history of cracking.
Try "www.TheEngineShop.com" this is a div of Bill Mitchell
I'm real sorry that it took me so long to get back.

Later

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perce111
78T-Top...IAM TOO

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erl
Journeyman

Posts: 8
From: Albuquerque, New Mexico U.S.A.
Registered: Aug 2004

posted 08-27-2004 02:11 AM     Click Here to See the Profile for erl   Click Here to Email erl     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by Percy Hazel:
Yes they have a history of cracking.
Try "www.TheEngineShop.com" this is a div of Bill Mitchell
I'm real sorry that it took me so long to get back.

Later


Did a temp test on the radiator with a digital laser gun after I got the car hot. The hose side is 133 degrees the opposite side is 97 degrees, the block temp was at 177 degrees. These temps I believe are within normal readings? So I figure I have a bad gauge. Replaced the temp sending unit already. I wonder what would make the gauge peg like that, yet still fluctuate a little? Also did a carbon monoxide test on the radiator, it showed none. Thanks for the tips.

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