Need cooling system help!

[KAed 240]

I bought the car about 2 months ago, before me it had been sitting in a lot for 14 years, untouched. Well I got it and started the whole preventive maintenance deal, before I ever drove it I changed the radiator hoses, thermostat, radiator cap, vacuum lines, brakes, etc.

Since then I've just rolled over 2.5k on the odo, yesterday I was heading home and the car started running hot, so I pulled over and checked under the hood and steam was spewing from the radiator cap, it was still under warranty so I went and had it replaced just in case.

So tonight I leave the house and a mile or so it starts to overheat again, so I turn her around and once I'm home I checked my antifreeze and it was nasty, so I flushed it and changed it out. After that I went for a test drive and before I could even make it out of my driveway it's overheating again, so now she's parked until I can figure out whats wrong.

My dad said he thinks it could be either the water pump or the thermostat isn't opening, but the thermostat is less than 2 months old and the water pump isn't leaking nor is the belt squealing.

My last 240 had a cracked block so I immediately jumped to that conclusion but pretty much ruled it out, no water in the oil, no condensation out the tailpipe, no loss of antifreeze, etc...

Sorry for the long read but I really need help on getting this fixed, it's the only vehicle I have.

Thanks in advance,
-Bryan

[OutToWinPAHC]

Check for intermix, if none then rent a cooling system tester. Test the system at 1.5 bar or about 17-18 PSI and it should hold pressure. When I check them I let it sit for 15 minutes to make sure pressure is not dropping. If pressure drops check all hoses, and gaskets for external leaks. If it fails and you cant find an external leak then check compression. If compression fails then you need to pull the head, have it checked and milled and do a gasket.

If pressure hold, and there was no intermix then replace the T stat and see what she does. If that doesn't work maybe do the pump.

Make sure there are no radiator cracks, leaks, and the fan is working before hand.

[OutToWinPAHC]

You did bleed the system right?

[allenms240]

Hmmm,
Pull the radiator out and flush it thoroughly? Make sure its not clogged. I had a overheating problem which turned out to be a cracked radiator. Also what outtowin said, make sure you bleed the system of bubbles. Google it.

[alms24sebring]

This happened to me too. Overheating => replaced thermo w advanced auto => worked for a month maybe => overheated again => bought a quality thermo from Nissan => fixed

It has to be a bad thermo or you just have to bleed it right.

The thing Im bothered about is that you say it sat for 14 years untouched. Maybe the coolant solidified or something, but Ive neverseen that. At the same time Ive never seen a car sit for that long. I would take off the top hose from the radiator and spray water thru the motor with a garden hose, with the bottom hose off so it can drain until its perfectly clear water. I would do this while changing the thermo again, then bleed it good.

btw, you said it only had 2500 miles on the odo? Thats an instant classic worth billions I tell you!

[OM3GA]

Get a Good radiator if you can afford it, maybe mishimoto at the cheapest. Put a hose into the upper hose port on the intake mani with the water pump out and flush out all the crap that may be in there. Then dry it off put in the new water pump. Reinstall the hoses and use a burp funnel to do it the right way.

Or you can try jacking the front of the car up or driving it onto ramps to get the front up as high as possible and run it like that. The burp funnel is the cleanest way, just make sure the heater is on full blast, put the burp funnel on and fill it up about half way then you'll be fine after running it and revving it for awhile maybe 15-20 min.

One of these bad boys

[KAed 240]

Thanks for the responses guys.

I ordered a Nissan Thermo, Water Pump, and a Calsonic Radiator, all OE. They should be here within the next couple days.

Yes I bled the system thoroughly for any air before I left.

The car has just over 65k on it, 2.5k of which came from me. haha

After I get the parts in hopefully that will fix the problem, hitching rides to school and back sucks.. -.-

[alms24sebring]

O ok got you. Still, pretty good milage.
Uh hold on, but if it is already a new radiator, thats good.
better safe than sorry tho I guess. keep posted

[OutToWinPAHC]

Always test first...... hate to find out all it was was a loose crossover hose clamp.

[s13sickboi]

One of these bad boys

nissan provided a bleeder screw on the intake manifold where the upper rad hose mounts. you dont need those funnel things.

[KAed 240]

All the parts arrived today: radiator, T stat, and water pump.

Went to install them one at a time running the car in between to see which one was the problem, turns out it was the water pump. I could see steam coming from it after I put in the radiator; changed the pump and problem solved! Is it normal for water pumps to go out around 65,000 miles? Thanks guys for all the help!

[alms24sebring]

U mean like the pulley was turning but the pump wasnt, like the bearing broke?? havent really seen that before

[KAed 240]

Sooo... she's running warm again.. Was heading to school and as I turned into the parking lot the temp started to rise ever so slowly, got to the final dash before overheating and I cut it off just in time to roll into a parking spot. I am now 100% confused and the only thing left to do is go buy a compression gauge and pray its not my HG... Any new insight?

[badbob2121]

go buy a compression gauge and pray its not my HG

[Armstec_S13]

also check your coolant temp sensor, faulty temp senors tend to cause crap like that too, praying that it's not the HG

[OutToWinPAHC]

TEST THE DAMN SYSTEM..... Autozone, and advanced have the tester under loan a tool.

[KAed 240]

Armstic: If it were the coolant temp sensor wouldnt the gauge either peg hot or not move at all? Just something I heard, next chance I get I'm going to change both since they are cheap.

OutToWin: Havn't had time to go get one, will test when I get the sensors...

Thanks again for the help guys..

[OutToWinPAHC]

Dont over test either dont exceed 1.4-1.5 bar

[alms24sebring]

Dam thats weird. I would think the temp gauge would be hot or cold like stated before, or flopping up and down rapidly (like mine was). If it only overheats while moving slow, the clutch on the fan sould be weak. I dont really know what to say but I wanna doubt the HG.. unless your exhausting smoke.

[OutToWinPAHC]

A head gasket broken between the cooling galleys and the combustion chamber will cause smoke, broken between the oil galley and water galley will make intermix, broken between coolant galley and atmosphere will weep or leak slightly but let air in the system.

Don't play the guess what it is game, test the system, find out of there is a leak, then determine internal or external.

[KAed 240]

From what OutToWin says it sounds like there is a break between the coolant and oil. I was heading home and it ran warm, so I pulled off(at the same place my coupe blew a HG) and checked the oil, duh duh duhn.. there was intermix. I'm still going to run tests to check but I have a feeling I'm due for a HG change soon. Not all bad though, get the clean the engine bay and paint my valve cover..

[KAed 240]

Ran a compression test, tested 156, 83, 92, 161... well damn... Ordered Gasket set and started pulling the exhaust manifold tonight, anyone know an easy way to take the copper hose off the back of the manifold? it's rusted on.. Thanks.