What is wrong with my car?

Question

I have a 1991 Honda Accord LX and am having trouble with overheating and keeping coolant in the radiator. When the engine gets hot the coolant in the radiator is pushed into the overflow tank to the point of spilling out of the tanks cap along with the radiator cap. This occurs every time I drive it and I have to replace the coolant almost every day. The engine only overheats when the radiator dries up. I have been told I either need a new radiator or it is a head gasket problem. How do I know for sure?

Answer 1

Three of the most common failures for that little car.
1) Coolant cans don't come on.
2) Thermostat sticking closed.
3) Blown head gasket or cracked head.

Try this---> Start your car, ans stand in front of it. Have a friend turn on the A/C to MAX and listen. Did the fan come on? If not, this might be your problem, and now you need to identify the cause. Is it the fan relay or MAXI fuse, or is it the coolant sensor (1 of 2) that tells the PCM to turn on the fan. Or has the fan motor failed? If the fan works continue on to...

With the coolant full and the engine running, watch the dash gauge for the temp to rise to normal or more (NOT a lot more) and see if the upper hose is HOT or merely warm or cool. If it is not hot, the thermostat is stuck closed. Replace it. If it is hot, then continue on to...

With the radiator cap off and the engine running at a fast IDLE (NOT racing, but ~1500RPM) look into the radiator filler and observe the coolant flow. Does it appear to have a lot of bubbles or foam? If this is the case, you are in for a pretty hefty repair, as the cylinder Head will have to be removed to further determine the level of failure.

Good Luck

Answer 2

There's a lot of things that could be wrong. Here are some tests:

To check the thermostat, pull it out and put it in a glass of boiling water. If it doesn't open, that's your problem.

See if the cooling fans switch on when the gauge gets into the hot area or not.

Do a compression test. One or two cylinders will probably be low if it is a head gasket. I think this is the most likely cause of your problems, BTW.

There are not many tests you can do directly on the radiator. Radiators can fail through either rusting from the outside or clogging from the inside. If the radiator is green and crumbly, it may very well be the problem.

Answer 3

You may have a faulty radiator cap, thermostat, radiator, water pump, or cooling fan.

To check the following take the radiator cap off while cold and start the engine if there is air bubbles gushing out then you have either a cracked head or head gasket bad.

Leave radiator cap off and check for water flowing through the system , if there is none it is either the water pump,or the thermostat not opening after it has warmed up.

If you have proper water flow and nothing gushing out then the radiator cap is not venting correctly.


When temp gauge reads normal and the fans have not kicked on , then you have either a faulty fan or relay.

finaly if you have water flow, no bubbles, and fans are running, then you have a plugged radiator.


Sheeeeeewww....Hope this helps

Answer 4

in this order:
check thermostat to see if its opening and when your doing this you can also check the cooling fan operation at the same time.
then check further into it, i.e. head gasket or whatever but also remember that when it originally started this problem and you added coolant you could of created an air pocket in the system, it should have a bleeder valve right around where the upper radiator hose goes into the block.

Answer 5

i think it is a head gasket on it,,i own a repair shop,,in Tennessee,,and we do this kind of work all the time,,what it is doing is letting the compression from the engine escape in to the coolant chamber,,this builds up pressure,,and it has to go somewhere,,i have seen it blow radiators,,completely apart before,,and i have also seen people who was working on them get severe burns from this,,you need to be care full when around it,,and it running,,it needs to be repaired as soon as you can get it done,,if not you may ruin the engine forever,,i hope this helps.,,PS just because you dont see water in the oil,,does not mean the head gasket is good,,there are 2 ways a gasket can blow,,keeep this in mind,,and be carefull.

Answer 6

Well, there are any number of things that can make a car overheat, and what I will try to do here is explain how the cooling system works, where the potential failures are, and how to diagnose them without having to be a certified mechanic.

First of all, you have a radiator filled with a coolant and water mixture. The coolant has three important properties: it boils at a higher temperature than water, it freezes at a lower temperature than water, and it contains corrosion inhibitors that keep your cooling system from, for lack of a better word, rusting. Unfortunately, coolant itself is not very good at carrying away heat from the engine, which is why you have water in the system as well, as water is very good at exhanging heat. Accordingly, it is important that you have the proper mixture of water and coolant for your climate (which is about 50/50 in most of the continental United States.

Now, you have a hose that carries your water/coolant mix (hereafter referred to as just coolant for simplicity's sake) to your engine and another that carries the coolant from the engine back to the radiator, and this circulation is powered by a water pump driven by a fan belt or serpentine belt depending upon the design of your car.

Somewhere between the radiator and the engine you also have a thermostat, which is essentially a heat activated valve. Engines run best in a relatively narrow temperature band, so the thermostat is designed to allow the coolant in the engine to heat up to a certain point (say 190 degrees farenheit) and then the thermostat opens letting the waterpump force cooler coolant from the radiator into the engine which displaces the hot coolant there and forces it through the hose that returns it to the radiator to be cooled down again. Then the thermostat closes, allows the coolant in the engine to reach 190 degrees again, and the process repeats over and over again as you drive.

Incidentally, the water pump runs all of the time, obviously, so when the thermostat is closed it diverts the flow from the pump back through a Y-connection hose into the return hose for the radiator, but coolant does continue to circulate, just not through the engine. That coolant is trapped in the engine until the thermostat opens again to let it out.

Now let's take a look at the problems that may be causing your overheating, beginning with the simpler ones, and ending with the more complex (and expensive).

I already mentioned the importance of having the proper mixture of coolant and water. That is not likely to be your problem, but you can always find a gas station that will check that for you, almost always for free. They just use a little gadget that can measure the specific gravity of your coolant mix (antifreeze being lighter than water).

So the next thing one might try to determine is under what conditions is the car overheating? Does it only overheat when idling or in stop and go traffic for example, but not in highway driving?

If that is the case, I would look first to the electric fans mounted on the radiator. There are often two: one that comes on when the coolant in the radiator is getting to hot, and the other that comes on whenever you turn on your A/C (as running the A/C compressor adds heat load to the engine).

So if you are sitting still in your driveway, and the engine has reached operating temperature, but neither fan comes on, then you have one of three problems that are relatively easy to diagnose. Either the fan itself is broken, the thermal switch that turns it on has gone bad, or you have a bad connection to the fan or the switch.

It is relatively easy to see if it is the fan, simply by unplugging it, and making a little jumper cable from an old extension cord or some electrical wire. You take a couple of clothes pins or even rubber bands and attach one end to the positive and negative terminals on your battery and the other ends to the poles on the fan motor where you disconnected the wire. If the fan then works, you know that it is either the thermal switch or the connections in between. Then you look for corroded connections at the plugs or loose or broken wires, and if you find neither it is probably the switch itself.

But suppose the car overheats all of the time, not just from idling or sitting in traffic? Well there are several other things you can check easily.

When it first boiled over, was the coolant rusty looking? If so, it might be indicative of having left the coolant in too long, so that it lost much of its anti-corrosive properties and the result was one or both of the following: The inside of the radiator may have been clogged with corrosion or at the very least coated with it so that it cannot exchange heat readily--as a coating of corrosion can act as an insulative barrier to heat exchange. Also, the corrosion may have caused the thermostat to become partly clogged so that it is stuck in a partly closed position, impeding coolant flow to the engine. The latter is fairly easy to check with a reasonable degree of accuracy, without removing the thermostat.

In the morning, before you have run the car at all, start it and sit inside and watch the temperature guage very carefully until the engine reaches normal operating temperature. If, at that point, you see the temperature needle drop ever so slightly, that would be indicative of the thermostat having opened to admit cooler coolant from the radiator, and most likely that means the thermostat is working.

Now also, when the engine is cool, remove the radiator cap, and look inside the radiator. If the interior seems to be coated with an orange milkly residue, the radiator probably needs to be chemically flushed, and you can buy a radiator flush and do that yourself if you have any mechanical skills at all. Just follow the instructions on the bottle.

So what else could be wrong?

Well, the water pump itself could not be working, and not circulating coolant--though typically a water pump will begin to leak when it fails and you will see coolant coming out of it. Yours is on the end of the engine on the passenger side as I recall.

Still another possibility, perhaps the worst of the possibilities is a blown head gasket, and this is a little more complicated to explain, and expensive to fix, so I have saved it for last.

Your engine is comprised to two major parts--an engine block that houses your cylinders, pistons, crankshaft and various other components, and you cylinder head which houses your valves and the camshaft that operates your valves. There is a seam between the two, where they are conjoined, and that seam is fitted with a large sealing gasket with a great many holes in it. There are big holes that fit around each cylinder, and smaller holes that are situated over the passages between the cylinder head and the block through which oil and coolant are distributed (separately obviously). That gasket is held in place, indeed crushed into place, by a number of large bolts called cylinder head bolts (catchy, huh) that secure the gasket between the head and the block with the gasket providing the seal.

Well, for any number of reasons, this gasket can be blown out in places, producing gaps that can allow any number of things to happen depending on where these gaps are or how large they are. Coolant can mix with oil, or oil with coolant. Or if the cylinder seal is compromised you can lose compression or coolant or excessive oil can get into the combustion chambers. Any of the above can cause an engine to overheat.

The tell-tale signs of a bad head gasket are oil in the coolant, or droplets of coolant or muddy brown goop on the oil dipstick. You can also, if you are mechnically inclined, run a compression check on each cylinder, which essentially involves removing the spark plugs one at a time, and inserting in the plug's place a pressure guage. Below spec pressure, or uneven pressure from cylinder to cylinder of greater than, say, 15 pounds high to low, would indicate a possible problem, although low compression could also be a function of bad valves or worn piston rings.

Anyway, without actually seeing the car, this is about all of the help I can give you without more specifics. If you wish to discuss it further, please feel free to drop me a line at [e-mail]

Answer 7

Could be as simple as a thermostat, which is cheap to buy and easy to fix.

Are you sure all your hoses are tight, and your radiator is not cracked?

I'm sure either you or someone you know can replace the thermostat (a 15 minute job) before you try anything else. If that doesn't work, you'll have to take it to a mechanic.

Answer 8

it can also be your water pump...

if its a headgasket, it'll run rough & you may be able to spot the leak on your block, either by feeling around the head for air leaks
or seeing water spots from waterleaking from the gasket.

if its the radiator, then its clogged & either needs to be flushed or replaced..flushing a radiator is pretty simple, ask at any auto parts store & the directions are on the bottle..i'd go with flushing the radiator 1st, then look around the head at the gasket area for water residue, with the engine running feel your way around the head for air leakage.. & lastly, find your water pump & look directly below it for signs of water leakage..water pumps are designed to leak if the diaphram goes out, usually theres a hole underneath the pump for "peeing" when it goes out

i hope this makes sense & helps..good luck

Answer 9

could be radiator a hose but is probably thermostat to see if head gasket is bad check your oil to see if has water in it check water for oil content also when car is cold remove radiator cap fill radiator start car if blowing bubbles through radiator probably bad head but ive seen a car blow bubbles & a pcv valve fixed problem

Answer 10

CHECK YOUR OIL IF IT IS A HEAD GASKET THE OIL WILL LOOK BROWN AND MILKY TRY REPLACEING THE RADIATOR CAP OR THE WATER PUMP TO MAKE SURE THE WATER IS CIRCULATING CHECK THE THERMOSTAT ANY OF THESE WILL MAKE THE CAR OVERHEAT