Question about 1965 Ford Mustang

3 Answers

1965 Ford Mustang 289 overheats at highway speed

Hi, the engine gets very hot at highway speed. At idle and cruising at 40 mph the temp is normal. The water pump is new, lower hose has spring in it and heads are rebuilt. the thermostat is 160 degree with a 16LB cap. Also checked that the head gasket was installed correctly (front label faces to front of engine. Any idea? I also noticed that the head gasket covers one of the water jacket ports in front of engine and the other port has only 1/8" hole in the gasket. The gaskets are correct for engine but why block one port and restrict another? Any suggestions. Thank you.

Posted by on

  • Dave  C
    Dave C May 11, 2010

    Easy one, classic plugged radiator symptom.


3 Answers

  • Level 2:

    An expert who has achieved level 2 by getting 100 points


    An expert that got 5 achievements.


    An expert whose answer got voted for 20 times.


    An expert who has written 20 answers of more than 400 characters.

  • Expert
  • 137 Answers

A partially blocked radiator will also cause htis symptom. Had this happen on two cars in the past. Take radiator to shop for rodding out and cleaning.

Posted on Apr 22, 2009

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points


    An expert that got 10 achievements.


    An expert that got 5 achievements.


    An expert whose answer got voted for 500 times.

  • Ford Master
  • 783 Answers

If you have the head gaskets installed with front stamp toward the front this is correct. Cooling passages in the cylinder-head gasket must always go at the rear of the block to ensure proper cooling. This allows coolant to circulate completely through the block and heads on its way to the thermostat and radiator.
Usually if it overheats above 40 mph this idicates that exhaust gases are getting into the coolant either from a cracked or warped head. I would have a combustion leak test done. A combustion leak test is designed to check for the presence of combustion gases in the engine coolant. It should be performed when signs (overheating, bubbles in the coolant, rise in coolant level upon starting) point to a blown head gasket, cracked block, or cracked cylinder head. A block tester, often called a combustion leak tester, is placed in the radiator filler neck. The engine is started and the test bulb is squeezed and then released. This will pull air from the radiator through the test fluid. The fluid in the block tester is normally blue. The chemicals in the exhaust gases cause a reaction in the test fluid, changing its color. A combustion leak will turn the fluid yellow. If the fluid remains blue, there is no combustion leak.

Posted on Apr 16, 2009

  • Chuck Martin
    Chuck Martin Apr 16, 2009

    Or as Dave suggest maybe a partially clogged radiator.


  • Level 3:

    An expert who has achieved level 3 by getting 1000 points


    An expert that got 10 achievements.


    An expert that got 5 achievements.


    An expert who has answered 1,000 questions.

  • Master
  • 1,055 Answers

Your raidator fins my be clogged and also you shouldnt have a clutch fan on it it should be a locked fan!!!! for more air flow!!!

Posted on Apr 16, 2009

1 Suggested Answer

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.

Posted on Jan 02, 2017

Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

2 Answers


About 6.5 hours to do the job. Times their labor rate. Buy a flywheel. I can guaranty yours will be bad. Weather is or not.

May 15, 2015 | 1965 Ford Mustang

1 Answer

I have a 1965 mercury comet with a 289 v8. I want to know what type of differential I have in it so I can buy a new cover for it

Here are the spec's for the 1965 mercury comet, 289 V8:

For 1965, the Comet Cyclone was powered by the V-8 with 225hp, the same engine that was put into Mustangs. And for more power, there was a special high-performance package, better known as "Hi-Po," available with the Cyclone, and it shared the 271hp V-8 which, when installed in a Mustang, was known as the "K" code car. In the Comet, the engine code is "A." When equipped with the Hi-Po package, a 1965 Cyclone came standard with: 289 four-barrel high-performance engine, four-speed Toploader transmission, nine-inch differential, performance suspension, quick-ratio steering and 8,000-rpm Rotunda tachometer. However, the following items were extra-cost mandatory options with the 271hp engine package: four-speed transmission, heavy-duty front suspension, low-profile rayon tires and 42-amp alternator, according to 1965 sales information.

Its a 9-inch differential at best. Try this link for more data:

1965 Mercury Comet Cyclone

Apr 13, 2015 | Mercury Cars & Trucks

1 Answer

1966 ford mustang conv 289 2bl. When I got the

Try adjusting the air-feul mixture or just turn the idle up a little bit. For either of these there would be a screw adjustment near carb

Oct 21, 2009 | 1966 Ford Mustang

1 Answer

Size of valve springs fo 289 ford engine with 302 heads

its not that easy here are some of the things u need to know

* solid or hyd cam
* roller or flat tappet
* valve installed hieght
* rocker ratio
* cam lift

this is just a few things go to a head shop and they will choose the right ones

Dec 19, 2008 | 1965 Ford Mustang

Not finding what you are looking for?
Cars & Trucks Logo

776 people viewed this question

Ask a Question

Usually answered in minutes!

Top Ford Experts


Level 3 Expert

74945 Answers

Colin Stickland
Colin Stickland

Level 3 Expert

22095 Answers


Level 3 Expert

5467 Answers

Are you a Ford Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides