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
Cool heat; Warm but not hot output
Topic Started: Dec 23 2017, 09:32 PM (1,099 Views)
Maybemaybenot
Noob
[ *  *  *  * ]
As the title states, when I put on my heater on hi, it is warm to begin with but suddenly cools off. Further, my idle is somewhat elevated. When I crank the car, the idle is low for a minute or two, and then increases. The idle remains at this rate until the key is turned off no matter how far I drive her. I have read several threads about abnormal function of the blend door, thermostat issues, heater core/radiator/intake coolant pluggages et al. Before I did anything drastic, I grabbed my temperature gun and began scanning coolant lines and heater hoses. I registered significant temps closest to the engine anywhere from 180° to just north of 90°/100°. What puzzled me was that the steel tube that comes from the water pump to the bottom of the radiator. It had a temp north of 100° from the pump up until the 90 degree bend at which the temp fell like a rock down to like 80°. This discovery only added to my confusion. I have replaced the coolant temp sensor because I got a CEL. With the cold heat from the dash and the high ide, I wonder if it's all connected and if the strange variation in temperature is related to the whole thing. Am I on the right path? Thoughts and suggestions are valued and appreciated.
Offline Profile Quote Post Goto Top
 
Me and my metro
Member
[ *  *  * ]
If you have a 195* thermostat I would say it is stuck open.
Offline Profile Quote Post Goto Top
 
Maybemaybenot
Noob
[ *  *  *  * ]
Update:
I replaced the 195 degree thermostat, brought the car up to temperature while checking for leaks. I took her for a spin. the heater temperature roared out early on but soon fell off to about what it would be if using the fan only. Upon return, I scanned the temperatures and recorded as follows:
Top Radiator hose: 137
Hose at thermostat housing: 155
Bottom Radiator hose:112
Steel tube from water pump:89
Heater core inlet and outlet:107
94
Intake heater hoses:100
120
I am reluctantly going to research how to go about changing the heater core. In the meantime, I will go through one by one and verify the hoses to ensure they are clear. Anyone on the forum savvy on these temp variations?
Offline Profile Quote Post Goto Top
 
freegeo
Member Avatar


Where is the needle on the coolant gauge when you were driving. What was the outside temp when you took it for a drive?

Are you sure the coolant level is full and no air is in the system?
Edited by freegeo, Dec 24 2017, 09:55 PM.
Offline Profile Quote Post Goto Top
 
Maybemaybenot
Noob
[ *  *  *  * ]
Freegeo,
The dash temperature gauge is around half way btw C and H.

Outside temp here in eastern NC is btw 45-55 degrees. (its supposed to get to 31 degrees here tomorrow)

Yes she was and still is topped up with antifreeze.

thanks for your help
Offline Profile Quote Post Goto Top
 
freegeo
Member Avatar


The thermostat should stay closed to keep the engine warm. Your needle staying in the middle of the gauge shows the system it is working normal. If you are losing heat as you drive the heater core may be clogged.
Offline Profile Quote Post Goto Top
 
92blumetro
jack of all trades, master of two

back-flush the heater core a few times. use a good rad flush agent( I personally use restore plus, its used in commercial fleet big rigs)
flush entire cooling system, flush the heater core 3-4 times. flush out with water, use a garden hose adapter, let it run clear for an hour or more, alternating the water flow from the heater cores pipes. I also use air pressure to purge the remaining flushing agent/ water /
garbage from the lines.
I use red DELO brand 50/50 coolant, contains no silica. 1.2 million km lifespan.
heater core is annoying to change. but doable.
Offline Profile Quote Post Goto Top
 
Maybemaybenot
Noob
[ *  *  *  * ]
Update: I changed thermostat and did the heater core flush. I got a good flow both directions on the core. Ambient air temperatures here in ENC have been up and down. During that last nationwide chill around New Years, it got down to -1° wind chill here and then, no kidding, within a weeks time we had mid 70° temps. I checked the temperature of the air coming out of the vents and the drivers side was definitely the hottest at 94° then the two in the dash bezel read about 80° and 75° then the passenger side one read about 65°. All with an outside temperature in the high 50s to low 60s and with a piece of cardboard in front of my radiator. Furthermore, after I did the heater core flush, I ran the engine to normal operating temperature and the reading I got right on the head was only 150°. I bought a 195° thermostat and as I understand it, the thermostat won't even open up at 150°, right? One last thing, I scanned the black pipe that comes from the bottom of the radiator to the water pump. I want to say that I got temps at around 100 or so right there where the heater core hoses connect but as I moved my laser toward the radiator, the temperature dropped drastically to like 70° in the elbow above the transmission. Please tell me that's normal. I bet that pipe is hard to remove and clean out and mine doesn't even leak!
Offline Profile Quote Post Goto Top
 
sphenicie


What condition is your radiator/cap in?

I had a situation a few years back, where i replaced the radiator and then i could not build heat. I figured it was because the old radiator was a single row and the new one was a 2 row. That should not matter. I scratched my head for a while. It turned out that the NEW radiator had a tiny, tiny, micro tiny hole in the top, where the tank attaches. There was no APPEARANT loss of coolant, no wet spot, nothing. i drive over 1000 miles a week, and the coolant loss was not noticeable.
It turned out that the tiny hole was just enough to prevent the system from building pressure. it would only "leak" when the temp was near normal op temp, and then only a nearly invisable amount.

I suggest that you borrow a pressure tester from AZ or other parts store that loans tools.
The cap may also be shot, and not holding pressure.

EDIT: If your heater core is not clogged or leaking LEAVE IT ALONE! You should have been able to tell if it was clogged when you flushed it. I do not know what your maintenance routine is, or that of the PO, but Metros are often neglected. Because you mentioned that after the flush, it worked well for a brief time then suddenly stopped, some crud may have broken loose in the system and flowed up in there. Flush in forward flow direction and back flow direction and observe the flow rate as well as the water clairity.
Edited by sphenicie, Jan 15 2018, 05:22 AM.
Offline Profile Quote Post Goto Top
 
Maybemaybenot
Noob
[ *  *  *  * ]
Sphenicie, I thought the radiator cap too and went out and bought a brand new one. I did flush both ways after using the antiscalant and I got a clear flow on both sides of the core. I have thought of taking her somewhere and getting a full coolant system flush and see what the result is. Anyone have any idea how much that costs?
Offline Profile Quote Post Goto Top
 
geogonfa
Member Avatar


Just my .02¢...Remove hoses from the bottom of the intake manifold and see if the bottom of the manifold is clogged...
Online Profile Quote Post Goto Top
 
Metbob


I had the same problem, hoses cold little heat, just saw your post today. Fixed mine today, had a lot of air in the system. Replaced cap, no change, pulled the car up on a hill, and started burping the system. Ran the car without the cap on and watched the radiator. It would start to overflow and I would squeeze the bottom hose, air bubbles. I kept doing that until a steady flow of water was running through the radiator. Now the bottom hose is hot, and I have heat.
Offline Profile Quote Post Goto Top
 
sphenicie


Maybemaybenot
Jan 15 2018, 04:13 PM
Anyone have any idea how much that costs?

The kit is under $20. It is really nothing but a few different size t's and a spout. You cut in a t which has a garden hose fitting, that you cap when finished.
Offline Profile Quote Post Goto Top
 
geogonfa
Member Avatar


Here are a few flush kits...
https://www.amazon.com/Prestone-Universal-Flush-Fill-Fits/dp/B01MSJ3G4E/ref=sr_1_fkmr0_1?ie=UTF8&qid=1516108578&sr=8-1-fkmr0&keywords=Prestone+Universal+Flush+N+Fill+Ki

https://www.oreillyauto.com/shop/belts-hoses-16454/antifreeze-flush-kit-test-17481


Online Profile Quote Post Goto Top
 
freegeo
Member Avatar


Does the radiator fan kick on if you let the engine sit and idle? Will it get hot enough to do that?
Offline Profile Quote Post Goto Top
 
1 user reading this topic (1 Guest and 0 Anonymous)
Go to Next Page
« Previous Topic · Air Conditioning/Heating · Next Topic »
Add Reply