Welcome Guest [Log In] [Register]
Posted ImageWelcome to the all new Geo Metro Forum. We hope you enjoy your visit.

You're currently viewing our forum as a guest. This means you are limited to certain areas of the board and there are features you can't use and images you can't see. Registration is simple, fast, and completely free. If you're already a member please log in to your account to access all of our features:

Join our community!




Username:   Password:
Add Reply
Temp gauge going up and down...
Topic Started: Aug 31 2010, 01:41 PM (4,758 Views)
tbotello
New Member
[ *  * ]
Hello, my 92 4dr Metro has developed an issue where the coolant temp likes to bob up and down a little. Although, when it's not moving, the needle does seem to rest a little over half way as well. I had to take it to a mechanic to check it just over a week ago for the same issue since I was leaving for vacation the next day after the problem developed. He put what I can only assume was bars leaks in the radiator to see if that would be a quick fix. Anyways, I don't think it cured it, and I want to work it out now that I'm back from vacation. On top of that the alternator has about had it (batt light goes on and off), but I'll be replacing it in the next day or so anyways. Can any of you help steer me in the right area? Worst case, I think the head gasket needs replacing but I'm not too scared of that. That's why I got my Metro, ease of working on it with the help of you all.
Offline Profile Quote Post Goto Top
 
mcmancuso
Member Avatar


I'd think you may have a sticking thermostat.
Offline Profile Quote Post Goto Top
 
Johnny Mullet
Member Avatar
Kim John Mu

I would start with the T-stat also and be sure to properly burp the cooling system when done.
Offline Profile Quote Post Goto Top
 
mcmancuso
Member Avatar


If the mechanic put something in it, make sure you rinse it all out well, you don't want anything in there that could clog a small line or the heater core.
Offline Profile Quote Post Goto Top
 
mjspiess
Member Avatar


I had that problem & it ended up being a head gasket, but if I had replaced the water pump sooner I think I could have saved the hassle of replacing the head gasket. After replacing the t-stat, lower radiator hose, radiator, temp sensor, water pump & head gasket, the temperature gauge still read high although the coolant was not that hot. I ended up installing an after market temp gauge with numbers so that I could see how hot it was actually running.

If the battery light is flickering, it could be a bad alternator or the belt is slipping & also not spinning the water pump efficiently. I'd first start by checking the tension of that belt. If it's good & tight, see how well the water pump is pumping if you don't know how old it is. Once car reaches opperating temp (t-stat opens) squeeze the upper radiator hose & see if you can feel pressure building up. If not, the pump could be bad. Also, how fast does the temp rise?
Online Profile Quote Post Goto Top
 
slander
Member Avatar
Tech Certified

Johnny Mullet
Aug 31 2010, 04:37 PM
I would start with the T-stat also and be sure to properly burp the cooling system when done.
Agreed. Start simple, work up. It's most likely the thermostat!
Offline Profile Quote Post Goto Top
 
CityConnection
Member Avatar
Sir, yes sir!

Temp sensors can't read air, only liquid. If you have a dancing gauge you might have air in the system. This can cause the thermostat to open and close cyclically and the gauge will drop when the air hits the sensor.

1st thing to do is burp the system and see if that cures the dancing gauge problem. If it does and the problem comes back in a few days (or hours) then air is getting into the system from a bad HG, crack, or other opening in the cooling system.

Or it could just be a bad gauge, sender, wire...
Offline Profile Quote Post Goto Top
 
slander
Member Avatar
Tech Certified

CityConnection, I assume you work at a city or state data center or NOC? Look like the state has least multiple sets of OC rings. Nice connection. I wonder if it's burst-capable.
Offline Profile Quote Post Goto Top
 
Woodie
Member Avatar


Could be a bad ground causing the instrument panel to F up and there's nothing wrong with your alternator OR your temperature.

Whatever, flush that BarsLeak out as soon as possible and change mechanics.

Offline Profile Quote Post Goto Top
 
tbotello
New Member
[ *  * ]
mjspiess
Aug 31 2010, 05:44 PM
I had that problem & it ended up being a head gasket, but if I had replaced the water pump sooner I think I could have saved the hassle of replacing the head gasket. After replacing the t-stat, lower radiator hose, radiator, temp sensor, water pump & head gasket, the temperature gauge still read high although the coolant was not that hot. I ended up installing an after market temp gauge with numbers so that I could see how hot it was actually running.

If the battery light is flickering, it could be a bad alternator or the belt is slipping & also not spinning the water pump efficiently. I'd first start by checking the tension of that belt. If it's good & tight, see how well the water pump is pumping if you don't know how old it is. Once car reaches opperating temp (t-stat opens) squeeze the upper radiator hose & see if you can feel pressure building up. If not, the pump could be bad. Also, how fast does the temp rise?
Sorry, I've been away for a bit but thanks for all the responses. I noticed in the morning after sitting for the night, when I first hit the road, the temp went up to about 3/4 of the way up the gauge and then quickly settled at the half way point. I assumed the t'stat had kicked in at that point. As for how quickly/how much the temp rises, it's only a tiny amount on the gauge. Just 1-2mm, but it's fairly constant only resting occasionally. Forgive me, when "burping" the air out of the radiator, is that simply removing the rad cap while the allowing the engine to run? Do I add fluid during this time and when do I know all of the air is out of the system? Thanks.
Offline Profile Quote Post Goto Top
 
StevieC
Member Avatar


Alternator failing? Car overheating? Possibly a bad / slipping belt causing symptoms of a failing alternator + water pump?
Offline Profile Quote Post Goto Top
 
StevieC
Member Avatar


CityConnection
Sep 1 2010, 12:50 AM
Temp sensors can't read air, only liquid.
Really? A '92 Saturn that I had had the same part number for the air intake temp sensor and the coolant temp sensor, at least I thought it did!
Offline Profile Quote Post Goto Top
 
KY Metro
Member Avatar
Member

StevieC
Sep 1 2010, 03:10 PM
CityConnection
Sep 1 2010, 12:50 AM
Temp sensors can't read air, only liquid.
Really? A '92 Saturn that I had had the same part number for the air intake temp sensor and the coolant temp sensor, at least I thought it did!
They are the same on the Metro too.....but I think the ECM is looking for different values from each of them.
Offline Profile Quote Post Goto Top
 
Johnny Mullet
Member Avatar
Kim John Mu

Leave the cap off and run the car at idle having a bucket or pan underneath to catch the coolant and have fresh coolant ready. You will see coolant start to bubble out, but let it do it's thing. It's burping the air. After the burp be ready to add more coolant and let it burp again. This can take up to 30 minutes.
Offline Profile Quote Post Goto Top
 
tbotello
New Member
[ *  * ]
Johnny Mullet
Sep 1 2010, 08:12 PM
Leave the cap off and run the car at idle having a bucket or pan underneath to catch the coolant and have fresh coolant ready. You will see coolant start to bubble out, but let it do it's thing. It's burping the air. After the burp be ready to add more coolant and let it burp again. This can take up to 30 minutes.
So, will it just stop "bubbling" out? Is that when I put the rad cap back on?
Offline Profile Quote Post Goto Top
 
1 user reading this topic (1 Guest and 0 Anonymous)
Go to Next Page
« Previous Topic · Engine Tech & Diagnostics · Next Topic »
Add Reply