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Honda Prelude Devouring Coolant?

I must prepare you now before you read this: I know very little about cars or the terms to use. So I am going to get this out the best I can. My son owns a Honda Prelude 91. It was given to him by his grandparents. He has only had it for a couple of months. When he first drove it, it over heated. He checked the coolant level and it was very low (even though he swore his grandfather put some in). Added coolant - the car did not over heat anymore. However it started to act up when he wanted to start it. It just wouldn’t anymore. So he changed the spark plugs. The car worked perfect! He drove it without problems for about a month and then back to not starting again and it over heated. The coolant level was low again?? Where did it go? So he has added more. He says that when he checked the spark plugs again they seemed dirty as well. So he cleaned them up and then put them back in and the car seemed to start. He didn’t drive it anywhere though. Let it sit for a couple of days - tried to start it again and now nothing. I need to help him figure this out before we take it to a mechanic because I am afraid to be taken advantage of because of my lack of knowledge in this department. He is going to be using my car to go to work with and I “need” my car… I have my other children that rely on me for after school programs and getting to and from school. He loves this car so much and I really want him to be able to drive it. I hope I made this clear and it isn’t a stupid question… Thank you for your help! (PS, from what I understand the radiator is only about 6 months old)

when it does run is there smoke coming from the tail pipe, and what color is it and is there any kind of oder from the back?

Sometimes. Not every time. He said he thinks there is an exhaust leak and he can sometimes see the smoke coming from the bottom of the car where the leak is and then other times it will come out of the tail pipe. I do know that when I ride in his car for too long it does give me a headache.

Based on the symptoms (repeated overheating + “disappearing” coolant), I would be very suspicious about the condition of the head gasket. In other words, it is very possible that the coolant is leaking into one or more cylinders, and is being “burned” during the combustion process. That could also explain the “dirty” spark plugs and the starting problems.

A good mechanic can determine fairly easily if the head gasket is breached, and at that time you would have to decide whether this 22 year old car is worth the “investment” of big bucks for this repair. Just bear in mind that, because the engine has overheated repeatedly, the repairs could involve much more than just replacing the head gasket. I would vote to junk the car at that point, but, you will have to make the decision for yourself.

If he checks the oil, does it look normal or does it look like a chocolate milkshake?

@VDCDriver I agree that OP should stop driving the vehicle and have it thoroughly checked out. A head gasket breach was my first reaction; the engine should have a cooling system pressure test and an engine compression test to locate the problem. Agree that an engine overhaul in a car this old would not be cost-effective.

Would be nice if car was in California and was rust free. Might be worth saving

“Intake manifold gasket.”

If this was a GM V-6, I would agree with you that this is a possibility.
However, because it is a 4-cylinder Honda, I don’t believe that the intake manifold gasket could be the source of the problem, and I believe that the head gasket is the likely source of the problem.

Check the heater hose connection under the distributor, and check for an oil leak from the distributor causing the heater hose to swell up and leak.

Been there done that. My Son loved his 2.0L Accord. Unfortunately once the aluminum head has been overheated (warped) it is a losing battle.