sileightygx Posted July 6, 2011 Share Posted July 6, 2011 Just wanted to get some opinion from you guys. These are spark plugs from cyl 1 & 2. Kinda hard to tell with crappy cell phone pic, but the burn has a greenish tint to it. The rest of the spark plugs are normal darkish brown burns, which cyl 1 & 2 also looked like a month ago. My L24 just randomly started overheating, nothing extreme, but the temps rise up to about 3/4 and then come back down. Waterpump and thermostat are new, radiator is fairly new. almost seems to me like a headgasket..but dont want to jump to conclusions until i get coolant pressure/compression tester. Quote Link to comment Share on other sites More sharing options...
HowlerMonkey Posted July 7, 2011 Share Posted July 7, 2011 Fan clutch pulling air when sitting and warm? Does it heat up when driving over 45mph for a bit? Quote Link to comment Share on other sites More sharing options...
sileightygx Posted July 7, 2011 Author Share Posted July 7, 2011 Hey howler, thanks for the reply. The clutch fan is working and pulling air in..seems to be not heating up much more than normal for stop and go. However the car really does heat up once you are up to speed at 40+. I checked my ign timing yesterday, and it is still fine 19 idle, 35~ all in. any suggestions? I still need to go buy comp tester and coolant pressure tester. My comp tester got smashed during the move =( I am suspecting either I have a blown headgasket, or my radiator is trashed... Quote Link to comment Share on other sites More sharing options...
BluDestiny Posted July 8, 2011 Share Posted July 8, 2011 Maybe a stuck thermostat? MY friends honda was having the same problem, heating up when it was moving, but at idle it would drop down to normal. Changed the thermostat and no more problem. If it was a blown headgasket you'd be losing coolant one way or another(into oil, or burning it hence the spark plugs). Quote Link to comment Share on other sites More sharing options...
skirkland1980 Posted July 8, 2011 Share Posted July 8, 2011 (edited) Napa sells a kit called a block tester. It uses some kind of blue fluid. You pour a little into the tube thingy and put the tube thingy where your radiator cap goes, if the fluid changes to yellow you have a blown headgasket for sure. Not sure what they charge for that kit. Sorry for my 1st grade grammar but I don't know the exact name for that stuff. ok the part number is BK 7001006 it's $42.99. It comes with enough fluid to check dozens of cars. Edited July 8, 2011 by skirkland1980 Quote Link to comment Share on other sites More sharing options...
sileightygx Posted July 8, 2011 Author Share Posted July 8, 2011 Thanks for the reply guys. The thermostat is a new oem one, but i can pull it out and boil it just to make sure its working. It does seem to be opening as both radiator hoses are hot after when it should open. It doesnt seem to be losing any fluid so far either. I read a lot of people were saying the temp guage is not really accurate, but im just a little suspicious since it was fine just a month ago. Have to check the temp after I snag my friends cool laser temp gun. I did however drive the car around after work, and at idle/35mph it stays dead center for temp. Once I start driving faster 35+ I can see the temp start to crawl its way up to 3/4 and just stay there. Usually if it was a blown HG, wouldnt it just keep overheating into oblivion? The only cars I worked on with blown HGs you could definitely tell since they would heat up and never come back down. Quote Link to comment Share on other sites More sharing options...
Sam280Z Posted July 8, 2011 Share Posted July 8, 2011 Check for a collapsing lower radiator hose. Sam Quote Link to comment Share on other sites More sharing options...
sileightygx Posted July 8, 2011 Author Share Posted July 8, 2011 Hey Sam - the lower radiator hose is in good shape and isn't collapsing. Kind of wish it was so I can solve this Quote Link to comment Share on other sites More sharing options...
Ducer Posted July 23, 2011 Share Posted July 23, 2011 (edited) Hey Sam - the lower radiator hose is in good shape and isn't collapsing. Kind of wish it was so I can solve this Your plugs look good to me. I am sure your water pump is gone. On old cars, the water pumps blades get rusted away. Though it may not show any signs, inside, the blades on the water pump is gone, so it is spinning but no blades so no water is moving around. I've encountered this a few times before, WATER= rust, and it rusts away the impellers of the water pump, so no water is circulating. That is the other suspect, I suggest checking the water pump's impellers. Here's a link: LOOK AT THE PICTURE OF THE WATER PUMP IN THE MIDDLE OF THE PAGE: WOWZERS, I'VE SEEN A FEW IN MY LIFE. http://www.denlorstools.com/autoblog/2010/12/car-heater-blows-cold-auto-service-tips-part-2/ Edited July 23, 2011 by Ducer Quote Link to comment Share on other sites More sharing options...
Tony D Posted July 24, 2011 Share Posted July 24, 2011 " My L24 just randomly started overheating, nothing extreme, but the temps rise up to about 3/4 and then come back down. " This isn't 'overheating'... Have you verified the temperature of the thermostat housing or coolant going into the radiator when this happens? Stock gauges are about useless, use and I-R Gun or a meat thermometer. Sounds like a stock thermostat, actually, as mentioned above. Leaving the heater on "hot" without the fan blowing across it can sometimes cause this. Excursions are not an issue, and with the heat wave in the US recently people all over the US are getting a taste of what SoCal and the rest of the Desert Southwest deals with most of the year! The change from smooth warmup to spiking temps says something is going on, probably with the thermostat...but like I said, leaving the heater on can exacerbate it. Quote Link to comment Share on other sites More sharing options...
sileightygx Posted August 31, 2011 Author Share Posted August 31, 2011 (edited) Thanks Tony for the explanation! I actually haven't had any time to work on the car since I last posted, however will take a look today. It's hard to diagnose in the garage since it only heats up at freeway speeds, and stays at normal temps under 45mph or so. I have checked the temps on the thermostat housing/hoses with a temp gun, but that has also been at idle with no abnormalities. I have an old Omori temp gauge that I am going to install as well to get a better idea of the temp while the car is running at speed. Either that or pull over after the temps come up and check with the temp gun. I actually have only used the heater in the Z once, and it is always left on Cold. I am going to check if there is coolant flowing through the heater still at this point, possibly the gate is stuck open.. Edited August 31, 2011 by sileightygx Quote Link to comment Share on other sites More sharing options...
Pyro Posted September 5, 2011 Share Posted September 5, 2011 vacuum advance working? low ignition timing will also make it run hotter? but temps going up and down is most likely a t-stat issue Quote Link to comment Share on other sites More sharing options...
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