Hi gang... Recently I've had a couple issues with my temp gauge fluttering and bouncing between 12:00 and max; when it does the car runs really rough. It's worse if I give it much gas. This has been quite intermittant, but I'm wondering if maybe there's air in the system. Any ideas?? Vicdat
Sounds like your thermostat might be bad and not opening up....it will definetly run like crap when its overheating. But if there is air in the line then it could be up against the thermostat preventing it from getting heated properly.
There's a couple ways to do it. On a cold motor: Start the car. Take off the radiator cap Let the engine come up to temp. Keep topping off the fluid when it gets low (you'll start to see the fluid moving through the radiator with occasional air bubbles). The other way is to hang the resovior from the hood, fill it up & let the car run with the cap on. The air'll get forced out.
I was pondering this problem, have you made any changes to the system that would have got air in the coolant system? Or did you just get the car?
Best way is start the car cold, uncap the radiator, blast the heater at full, and let it spill over as the bubbles come out. Fill as needed.
with the motor turned off i fill it up, close rad cap, then run the motor for like 20 seconds to get it circulating, then open the rad cap, pulse squeeze both hoses, you'll see bubbles coming out with every squeeze until it's full.
for whatever reason i couldnt get 09 fully burped one time... so i pulled one of the hoses from the iac valve on the bottom of the throttle body. run the car till coolant comes out, then stuff the hose back on.
I'm going to check the thermostat tomorrow...I picked up a new one this afternoon. It was acting up quite a bit on my way home today; almost like what you people call "limp mode". Do I have to remove the alternator to get to the outlet? What about the single sensor that is on that housing?
OK so this morning I first replaced the coolant temp sensor (the single pin sensor on the upper housing...no improvement, then I put in a new thermostat...same thing. Both fans come on when the AC is on, but I don't think that they are coming on otherwise...could it be one of the other two sensors on the upper housing?
I have never had to burp the system it allways just works itself out just as long as you have fluid in the overflow container, at worst you would have to cycle the heater control from cold to hot to circulate coolant through the heating system. Anyways you have replaced the temp sensor on the intake pipe close to the altenator. This sensor is used to control your fan only......... I am guessing that your temp guage is still jumping around after your repairs You need to test the sensor for the temp guage not the fan sensor, this is the sensor that will send a signal to the ECU. The temp guage sensor is the top left sensor on the water outlet neck, in this picture I have replaced the original connector with a crimp on connector, it's just below the oil pressure sensor Start by making sure you have a good connection between the sensor and the plug, as I allready noted I replaced my original plug because it had a flakey connection If you still think your fans are a problem let me know and I'll show you how to wire them to be turned on automatically when the engine starts.
Thanx 2765...but the sensor I replaced this AM as the one on the left (single spade) under the oil sending unit; the connector looked pretty good. Anyway I only want to wire the fans up directly as a last resort. I'm pretty sure that I heard the fan running the other warm day when I restarted the car. Today I only see them run is when AC is on. It seems to get hot pretty fast and the needle once it gets to halfway makes little jumps hotter and hotter to max red...kinda scary. Could it be a relay??? Or some other obvious and easy fix ?
There is a relay for the fan heres how to test it The relay is in the main fuse box in the engine bay It also suggests testing the Engine Main Relay which is also in the main fuse box in the engine bay If all that doesn't work I would suggest taking out the thermostat all together so you are guaranteed a constant flow of coolant. This would just be temporary to see if it solves your overheating issue. It does mean it will take the car a bit longer to warm up but your running out of other options. It's a mechanical water pump run of the timing belt so it has to work, the only thing that ever fails on it is the bearing so you have to be pumping coolant.
It really sounds like the thermostat isnt opening or only opening partially. Have you replaced it yet?
I checked the new tstat and the old one in hot water and both opened up at about 180 degrees, so I went ahead and installed the new one with a new o-ring. So far I've replaced both upper sensors at the top (the temp switch, and the temp sensor) not the middle one, or the lower one where the t-stat is. The car starts up and runs fine for a few minutes until the guage gets to 12 o'clock but then every time I accellerate the gauge starts bouncing higher and higher and the car runs rough. It does this pretty much the same with or without AC on. I'm still only noticing the fans (both) when the AC is on....I'm at wits end. I also checked the relays and they seem ok
You have said before that the problem is intermitent and this normally points to an electrical issue Mecanical systems either work or don't but electrical systems sometimes become intermitent. Just look at our 4th gen starter issue. I think we can assume that your engine is indeed overheating, 2 different temp senders have produced the same results on your temp guage so we need to figure out why the cooling system isn't working properly. Thermostat - you have tested/ tried 2 of them and its not an electrical system so it's unlikely to become intermitent Radiator - your radiator may become clogged with crap and reduce the amount of coolant that can flow through it but once again it's a mechanical system so overheating wouldn't be intermitent it would be constant. Fan - the fan motor has brushes that wear out with time, never seen it happen but it is theoretically possible Fan Relay - relays are know to become intermitent, once again I remind you of our starter problem, I bet 7 out of 10 times I try to start my car I have to bypass the starter relay............. Radiator Hose - perhaps your inlet radiator hose the one attached to the thermostat is so old and soft that it is colapsing when coolant is sucked through it reducing the amount of coolant that can flow through the engine. Once again a mechanical system so not prone to intermitent falures I would recommend by-passing the fan relay and run your fan constantly as a test to see if that solves your overheating issues. I really don't trust 24 year old relays and have run the cooling fans on my Celica constantly for the last 2 years. Your probably going to burn out the fan motor a bit sooner and your going to waste a bit of electricity but your not going to do any harm to the engine. How long have you owned the car? Has it allways had this problem? Have you ever used a "STOP LEAK" product in the cooling system? What does the coolant look like?
Good points 2765, I appreciate your insights and suggestions Thi problem is now consistant...at this point I'm leaning toward flushing the radiator...I know the history of this car dating back to around 2008 when my best friend bought it. He did a lot to it before he passed away but I don't think that the radiator has been serviced
theirs only 2 real scenarios - either the coolant isn't flowing fast enough - it's not getting cooled enough when flowing through the radiator So you have to determine if its a flow rate issue or an inability for the heated coolant to cool back down. Do you have an infra red temp guage ? Their pretty cheap to get, if you can measure the temp of the 2 radiator hoses once the engine is warm, hopefully the one attahed to the thermostat is quite a bit cooler than the coolant return hose.
Before you do anything else, do a compression test. How do your spark plugs look? My old white '89 did the same thing. I had to do an upper rebuild (head gasket)
Latest Update: I'm having a mechanic check it out: He said thes compression is 185 across the board, the fans are working, and the water is flowing, and that the temp isn't going over 200 degrees according to his laser...all the sensors seem to be OK too. He thinks it's the cluster or temp guage that is the culpret. When the guage starts "spiking" thats when it runs rough. What are your thoughts??? I need answers quick (this is my daily driver, and I hate using my kid's Sentra). Vicdat