Overheating problem

[180cruiser]

Hopefully someone can shead some light here.

A couple of days ago my stock ka24de (200,000 miles) started overheating. When it happened I had just turned on the heat inside the car and no hot air came out of the air vents. Just after noticing this I looked at my water temp gauge and it went from normal temp all the way to Hot is just 3 seconds or so. I immediately turned off the car and pulled over. Popped the hood and the engine was not unusually hot.(the car had only been running about 10 mintues). The radiator was a quart low on coolant so I filled it up and headed for home. It was fine for 10 minutes and then overheated again. I thought. okay, sticky thermostat. I had the thermostat replaced and it still overheats. It always does it within 10 minutes of starting and then cools itself off without stopping the car. It has used up some coolant and my mechanic says blown head gasket.

I do not see white smoke, but you can smell coolant in the engine bay and a little out the tailpipe. The oil looks clean and I do not see oil in the radiator. Spark plugs have normal wear with no sign of coolant. I'm stuck. Any ideas??

[rotorimp]

Does sound like a HG--what is your compression like? Do you see bubbles when you open the rad. cap (open when cold)

[180cruiser]

I have not done a compression test yet. Tonight when I get home I'll check the radiator. After posting this thread I found others on the forum with the same problems. If it is a head gasket is it worth fixing? 200,000 miles on the motor and I'm going to have to pay someone to fix due to my work schedule. I'm wondering if my money is better spent somewhere else. I'm considering an SR swap. What do you think?

[NotDave]

its all depends on what you are looking for in your car

the ka can easily hit 300k fyi

[180cruiser]

Okay, I did see some bubbles as if there was air coming up from somewhere. Maybe 5 or six bubbles. Then they stopped.

I planned on doing an SR swap sometime in the future when I could afford another car and the 240 would go in the garage. Now this has happened unexpectedly. I figure if I have the head gasket replaced and with the possiblility of a cracked head, it's gonna cost me at least $1000. While I'm into it replace the timing chain that was already clacking very loudly and water pump now I'm at $1,500. That would get me back to running and maybe get me to 300,000 miles.

Or I invest the same $1500 toward the sr that I wanted to do in the future anyway. Keep in mind that the car would still be driven daily. Thoughts??

[180fan]

I'd look around for a leak. If you can smell coolant, you've probably got a leak. before going out to buy a replacement motor for something that could be as minor as coolant coming out the weeper hole on the water pump, I'd poke around a little more.

[180cruiser]

Pardon my ignorance...what is a weeper hole? If it were leaking at the water pump would I notice it on the floor? I've not seen any dripping while the engine is running or parked and I have a painted garage floor so it would be noticeable if I had dripping.

Also, SR swap is out of the question right now so if it is a head gasket I'm going to replace it.

Thanks for the response.

[rotorimp]

the weep hole is on the bottom of the Water pump snout. Since you had the t-stat replaced it is possible that it has an air pocket--does the fan feel like it has good tension (not grindy or freewheeling)? If the compression is good--have the system pressure tested. between those two tests you should be able to get a good diagnosis.

BTW--is the rad cap good? check all your hoses

[Reese]

Im having a the same overheating problem with my 240sx did you find any solutions? The car will ride fine for the first half and hour then the temp gauge will rise to H. Let the car cool down and temp will go down, the car rides fine, no weird noises. So far from reading I got it could be air bubbles, HD, water pump, leak, and timing,T-stat. I was wondering which is most a common problem? and if fixing any of those worked for anyone?

[coupe240sxguy]

also possible, cracked head

[rotorimp]

I wouldn't go straight to a cracked head unless when you pressure tested it you found the leak to be in the combustion chambers or there was coolant in the oil. Start with a compression test/pressurize the cooling system. The only sneaky problem i have encountered was a radiator that would swell up when hot and block coolant (VW).

[Reese]

I found a leak right underneath where the water pump is. Filled the radiator with water and coolant, and thats was coming out from the leak. possible water pump leak???? maybe that would explain why the car runs hot towards the end of the day when all the liquid totally leaks out?

[rotorimp]

Sounds like the weep hole on the neck/snout of the water pump.

[240sxmech]

since youve ran it hot a couple of times you definetly need to do a block test to make sure you sisnt blow the ehad gaskdet also.let us know what you find

[Reese]

got it fixed today, there was a leak in the water pump, replaced with a new one and the car runs good again.