My daughter�s 96 Zetec has been over heating. Did a flush, changed the thermostat, etc. No hot air out of the interior heat so figure it is the water pump. The interior heat will come on intermittently. When it does the temp gage goes down. The car is definitely over heating as steam coming out of overflow. Many hours later pull the engine apart and removed the water pump and looks fine. Am I missing something before I change the water pump and spend the many hours required to put it back together?
Rich S
Are the radiator fans coming on? And you might also want to check if the radiator is plugged.
Backflush the heater and radiator, also maybe replace the pressure cap. I would change the pump, if it is plastic impeller, impeller could spin on the shaft when hot. The head gasket could be bad, but the heater should still work as far as I know. Cooling fans are trouble, easy test see if it comes on with a/c on. Then see if it comes on with warmup "m" or so on the normal scale.
Both fan speeds come on. I plan to back flush as much as I can and replace the water pump. I am also of the theory that the impeller is slipping on the shaft when hot, that is why the heat sometimes works. What a pain to get the water pump out. Then got the wrong water pump, so watched football yesterday. Hope to finish tonight.
Rich S
OK It was not the water pump. The system was flushed with and with out the thermastat through the hose near the radiator on the passenger side. This is the heater hose.
So every thing is fine for the first 10-15 minutes. Heat works and temp is stable. After that it acts like there is no flow. Temp gage goes up and the interior heat blows cold. If I rev the engine the flow seems to pick up and the heat gets hot and the temp goes dowm. The drive belt is less than a year old and I put on a new tenioer. Belt seems tight.
I am confused. When the engine gets hot something seems to clog the water flow. Any ideas?
Rich S
Originally posted by Tony2005:
... And you might also want to check if the radiator is plugged.
One of the first things I did was dumpp water through the top hose of the radiator. Seemeed to flow fine. The part I do not understand is that the interior heat goes away. If I read the diagrams on the water flow right, the water pump pushes the water out of the block in to the thermastat housing. With the thermastat closed the water goes through the heater core. With the thermastat open it goes to both the heater core and the radiator. So if the radiator was clogged I should still get heat into the heater core.
Rich S
See if a hose collapses. The bottom hose maybe. The heat may drop a bit if the thermostat opens and lets the water into the radiator. The cooling fan should trigger and lower the temp, then it should cycle warmer, fan on, cooler, fan off warm again etc. to regulate the temp. You will see coolant gurgle a bit in the reserve tank when the thermostat opens up.
If the head gasket is leaking combustion into the cooling system, the resulting air pockets can block flow. Revving the motor can sometimes move the air and there will be flow again. This could explain your overheating and heat problem. Since a head gasket is not exactly unheard of in these vehicles, you may want to get it checked.
Originally posted by branchingout:
If the head gasket is leaking combustion into the cooling system, the resulting air pockets can block flow. Revving the motor can sometimes move the air and there will be flow again. This could explain your overheating and heat problem. Since a head gasket is not exactly unheard of in these vehicles, you may want to get it checked.
Here is a cheap quick way to test.
Fill antifreeze to the brim on recovery tank (leave cap off). Remove all spark plug wires. Remove all but one spark plug and have someone crank the engine. If the antifreeze bubbles over, there is leak from that portion of the engine (or cylinder). If not, go to the next cylinder, and then the next.... Note, it could be more than one area or more than one cylinder. Good luck.
Thanks for the advise. Now that I have ruled out the pump I am leaning toward the head gasket. I like the test with the plugs out and look for bubbles. I plan on doing a compression test but this may a quick way to get the answer. I had thought about collapsing hoses but forgot to check.
Rich S
I have started to take the head off to replace the gasket. Another pain. Last time I started it there was a smell of exhaust and gas in the coolant overflow tank. This was brand new fluid. After all this work the car better start and run well. Thanks for the help.
Rich S
You could smell gasoline/exhaust in the coolant tank. I hope the head gasket fixes your problem..Maybe there is a large blowout in the gasket?
After working on changing the head gasket for hours and days, can not work on it full time, it appears to have fixed the problem. Does not overheat, runs better, and the heat inside works.
By the way the new gasket was a multi layer metal gasket wihile the old one was a sturdy fiber gasket with metal rings around the chambers.
Thanks for the help.
Rich S
Good to hear you succeeded with the repair! Congratulations
Could you see a break in the old gasket, I have seen it where the material near the cylinder ring erodes.
That is the amazing part. The gasket and the block and the head did not show any real evidence of blow-by or erosion. There was some pitting in one of the combustion chambers but nothing serious. It was hard to clean the head and the block. Would not come off with solvents. I used a dremel and a fine fiber sanding pad. Also the head did not semed to be warped. I ran a compression test before we pulled the head and got 150 on 3 cylinders and 175 one. Seemed a little low but all with in range of each other. So after all the work of pulling the head I was concerned that I had just wasted a bunch of time but has been running great for almost a week now.
Rich S