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1993 Acura Legend Cooling System

I posted last week about the cooling system but I didn’t take everything into account and have to start from scratch. Last week I noticed the fans were not coming on so I replaced the cooling fan switch located in the lower tank of the radiator where the hose comes from the engine. This didn’t fix the problem and I noticed that the top hose out of the radiator was getting hot and the bottom one wasn’t so I replaced the thermostat and that also didn’t work. I am almost positive that the radiator cap is good because I cracked it to see if it was holding pressure and it was. The system is full of coolant. The next step is to replace the water pump but as with most things in this car it is a pain in the rear to replace so I figured I would ask to see if anyone had another idea. The pump was replaced 50,000 miles ago, it is not leaking or making any noise so I don’t see why it wouldn’t be working but it doesn’t seem to be working. Recap; I have replaced the fan switch because they are not coming on but then found it was because the lower hose wasn’t getting hot coolant so I replaced the thermostat and still nothing. Thank you for any recommendations and your time.

Sounds to me like its just a clogged radiator.

Having the cap hold pressure also doesn’t tell you it is good. How much pressure does it hold? Its probably supposed to pop at 15 or 16lb - and then close again down under that. For the $8 or so you might as well just put a new one on. In any case, its probably not the problem.

So should I drain the system and run some water through the radiator and the block and see what happens? If it doesn’t come out of the radiator it needs a new radiator and if it does come out of the radiator I need a new water pump?

You were having trouble getting the sensor out, how did you get the cooling fan switch replaced? Were the threads stripped?

I would pull the radiator and bring it to a radiator shop to have it tested.

They ended up being fine. I brought it to a shop down the street and they hit it with an air gun and it came right off. I threw a thin layer of tape on the threads and put the new one on. I have been testing the system so it has fluid in it and it hasn’t leaked yet. If I can ever get the car up and running again I will be keeping a close eye on in for a while to make sure it isn’t leaking but I think it will be fine.

The lower radiator hose should not be getting hot, at least not very hot, just warm. But if the hose is just warm, the engine should not be overheating. You can remove the radiator cap, start the engine and let it warm up. Once fully warmed up, open the throttle and run the engine between 2-3000 rpms and you should be able to see the coolant moving in the top tank.

The coolant level may rise a little but not too much. If a lot of fluid overflows, that would indicate a clogged radiator. If the coolant only rises a little and the coolant is moving vigorously, then the pump and the thermostat are good.

Now turn on the air conditioner. Both fans must come on, if one doesn’t, then that fan is bad and must be replaced. If neither come on, then you have a wiring problem. If both come on, but you overheat when stuck in traffic, then the fan switch or its wiring is defective.

If you are overheating at sustained highway speeds or when going up hill, replace your radiator cap. Don’t bother with testing it, just replace it, the cost is not great enough to worry about and most of the time, that does the trick.

My bet’s on the radiator being plugged, I’d just replace it, no surprise that a '93 would have this problem. They’re $90 - $120 from Rockauto for your car.

Somebody needs to figure out keith’s issue with the board’s software so he can just get all of his thoughts in one post window.

FIY, I thought the problem might be in my computer or my ISP, but I have the same problem with my computer on two different Comcast ISP’s and with two other computers, one being a new windows 7 system on Comcast and using IE8.

I have been registered under this name ever since car Talk required registration. I wonder if there is not some residual code in my account from the old days that is interfering with my account today.

Any chance this car could be having a head gasket issue? These Legends have been known to develop head gasket problems.

I did a compression test and it came back ok. I am still scared it could be bad but the compression test said it was ok…

I re-read the original post and noticed he didn’t say anything about overheating. I wonder if he is trying to fix a non-existant problem?

So I am about to try this let me know if I am doing anything wrong. I am going to take the radiator cap off and start the car. I should expect a bit of fluid to come out but not to much? Does that mean I should expect to loose a cups? Thanks for the input.

It is overheating. Mostly if I am not moving.

The fan is not working and the car is overheating while not moving, You have to fix the fan so only do the fan test with the AC. And yes, a cup is about what you will lose, but only as you rev the engine up. If you rev it up very slowly, you might not lose any as it will flow into the overflow tank.