How to diagnose overheating engine.


I have a Ford F-150 1995 model it has a 302 in it. My question is, it keeps overheating I change the water pump about 6 months ago, it has a new thermostat also, the water wasn’t circulating in the radiator so I flushed it 3 times took it out and made sure everything was washed out of it, so I put it back in and the water is moving through it just fine now, so I figured I had the problem fixed well I don’t its still running hot . Do you have any idea what else it could be that’s making it run hot? I’m baffled and out of ideas. Hope you can help thanks. – Kirk

Here are the steps I use when diagnosing an overheating issue…

1. Check the radiator cap with a tester. A bad radiator cap will keep pressure from building and can cause an engine to overheat.
2. Pressurize the cooling system and check for leaks.
3. Have the hoses been changed lately? A soft radiator hose can collapse and restrict flow of coolant to the engine.
4. If the radiator was plugged and required a flush, maybe the engine has a blockage as well. Was any radiator stop-leak product used in the past? They can cause issues with head gasket coolant passages and other tight areas.
5. I have had brand new water pumps fail shortly after install. It’s possible that at higher RPMs the impeller is spinning on the shaft, reducing coolant flow.
6. Check airflow, fan clutch or electric fan if equipped.

Overheating issues can be a real pain to diagnose. Many shops and owners just start replacing until they find the culprit.

Good Luck,


Posted: 28th October 2013  |  Author: Kevin Schappell  |  Category: Cooling, Engine

Air Pocket In Cooling System?


Does an air pocket in the coolant system cause a leak?

Three days ago I got a dealership to replace a cracked water pump on my 2007 chevy Impala. They replaced the pump but now there is a very small amount of coolant dripping every hour or so. I took it back to the dealership and told them the problem and they told me there was an air pocket and that I was to drive normally and it would take care of itself.



If the coolant is dripping from the overflow tank, I would not be concerned about it, but if its coming from the engine, specifically from the water pump, I would say they need to fix it. Keep watch, and check the coolant level on the overflow tank to see if it drops. If it continues to lose fluid over the weekend, I would take it back and insist on them fixing it.

Posted: 23rd July 2009  |  Author: Kevin Schappell  |  Category: Cooling

Winter Car Care Tips

It’s getting to be that time of year, time to break out the Halloween costumes and get ready for the cooler weather. Now is the time to start thinking about your car and what it needs to survive the bitter cold of winter.

The most critical and often overlooked part of your vehicle is the cooling system. Without the proper protection, your coolant can freeze in the winter temperatures and destroy your engine. The coolant in your engine is a mixture of water and anti-freeze, which is supposed to lower the freezing point of the coolant. If the ratio of water to anti-freeze is wrong, the coolant mixture will freeze. Since water is one of those goofy liquids that actually expands as is freezes, it can exert extreme forces on your engine and actually crack the engine block. You can check your coolant’s freeze point with a simple tool called a Ball-Type Tester. You suck up a little bit of coolant into the instrument and count the number of balls that float. Then using the legend on the tool, you can determine the freezing point. There are also testing strips available, which you dip into the coolant similar to a pregnancy test to check the freezing point. If your coolant is more than 2 years old or you have over 30,000 miles it should be changed regardless of the freezing point.

The last thing to check on your engine is the fuel system. A bottle of gas line anti-freeze should be run through the system before the first flake of snow falls. The gas line anti-freeze will absorb any residual moisture in the system and keep it from freezing your fuel lines. Water can get into your fuel tank from a bad batch of gasoline at your favorite gas station or a faulty gas cap.

Once your engine is protected, you should turn your attention to your tires. Check the tread depth and pressures before wintertime hits. The pressure in your tires can drop as the temperatures plummet. If your tires are getting worn, I would suggest replacing them to get the best traction in the winter months. You may even want to consider getting an inexpensive set of steel wheels with dedicated snow tires for the winter months. All-Season tires do every season well, but none of them excellent. By running a set of winter tires, you will get the best winter traction possible and keep your car on the road where it belongs.

Your paint will also need some protection from all the salt and chemicals on the road. Make sure wash your car well, and then apply a liberal coat of wax over the entire car. You can also wax your wheels if you have aluminum wheels, which will help to stop pitting and keep the wheels clean. The biggest mistake I see people make when washing a car is to not rinse their wash mitt or sponge, or rinsing it in the wash bucket. Make sure you rinse off the sponge or mitt outside the bucket with your hose. This will keep the dirt that you just wiped off the car from becoming sandpaper and you clean the rest of your car.

A good first aid kit is valuable any time of year, but what else should you have in your trunk? A good ice scraper, bag of salt or sand for traction and a blanket incase you are stranded and need to keep warm are all vital. If you have a rear wheel drive vehicle, extra weight in the trunk will help with traction. A bag of cement or sand can give you the needed traction in the winter months.

Good luck and safe driving,

Kevin Schappell

Posted: 4th October 2006  |  Author: Kevin Schappell  |  Category: Body, Cooling, Site News

Car Overheating



My 1987 ford mercury monarch sustained a broken heater hose, was towed into the garage and repaired. The mechanic ran the engine at idle for over an hour and declared it repaired and fit to drive. I drove the car about three miles, the engine light came on, the car overheated. I was towed back to the garage coolant was added again, no leaks were seen, the coolant was circulating, the engine was run for an hour, hose temp were 170 degrees and the car was test driven. Again I left the garage and again after 3 miles the car over heated and had to be re-towed to the garage. Can you give any help or explanation? The mechanic can’t explain.

Thanks for you help.




It could be a few things… The waterpump could be bad, even if the water is circulating at idle. The impeller could be loose on the shaft, and at higher engine speeds will not spin, thus causing your overheating since no water is being circulated. It could also be the belt, clogged radiator or extremely lean running condition, but my bet is on the waterpump.

Good Luck,


Posted: 5th July 2006  |  Author: Kevin Schappell  |  Category: Cooling

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