95 GEO Metro 3 cylinder overheating

[Syberfinder]

I replaced the water pump in my 95 Geo Metro over a month ago and just the other day it decided that it wanted to overheat. Today I performed a complete coolant flush and put a new thermostat in. The thermostat was a Valucraft from Auto Zone that looked nothing like the thermostat that came out of the GEO or the photo in the repair Manuel. I ran it for about half an hour and made sure the radiator fan worked, then took it on a fifteen minute test trip to see if it was fixed.

Long story short allthough it is not as bad my GEO is still overheating what should I look at next?

[brivers]

Plugged radiator. Flush is not always a sure fix.

[Crvett69]

if you get car up to operating temp and feel the rad fins it should be same temp all the way across, if its hot in middle and cool on ends its proably partially blocked, make sure thermostat is in right way ( spring side toward engine) and that its not stuck, could also have air in system, takes a while to bleed it out

[Johnny Mullet]

Originally Posted by Crvett69

could also have air in system, takes a while to bleed it out

I agree! It can take 30 minutes of running with the rad cap off until all the air is bled out. Jack the car up so the rad cap is higher than the rest of the engine and bleed all the air out. This takes time and patience.

[Syberfinder]

Okay Guys I finally got some spare time to work on this again. I tried everything that you guys put out for me to try. The heat across the radiator seems even and Jacking up the front end and running for half an hour seemed to take care of the air pockets in the cooling system. My guess is that the radiator may require a good rod job, can they be worked on?

[redpepe]

hi syber,
i recently had this problem and after replacing everything found that the rad fan was running slow. it appeared fine but it was not fast or powerful enough to actually cool adequately. i'd never run across such a problem before. my experience with any substantial size motor is that they either run or die completely. not sure how one would test for such a condition .... the fan always appeared / sounded to be moving well. i discovered the problem by accident.

i replaced the fan motor and it seemed to be fine for a short while but the head gasket finally blew [150/150/70psi, never used oil] after 326k so, overdue, i'm finally rebuilding the engine. looked into jasper engines [3yr / 100k i believe] and an outfit in spokane that says they do a 7 year / 70,000mi warrantee .... but decided to have it fully remade by a local fellow who had done some other engines for me years ago ..... megamotors in simi, ca.. going for an extra engine balance and ss valves ..... and considering some port work but it seemed to breathe well to me given its efficiency and longevity.

[Woodie83]

In Oregon in February his fan is never coming on, I doubt very much that is the problem.

I doubt it was your problem either. Your engine was over heating because one cylinder was shot, and you were running the piss out of the other two just to keep going.

[redpepe]

hi woodie,

possible but not likely. the 70psi is post head gasket blow out..... it was low before but not so bad. the cooling was like a rock overall ..... almost never varied. then the fan problem and replacements et al and the cooling settled down to 'normal' for a while until it went hot one afternoon and stayed hot and started to lose water from the cooling system.

you're right though, multiple problems and multiple simultaneous repairs make absolute diagnosis more difficult.

it did work hard for 326k .... i pull a trailer with mine ..... time to give it some new life.

[doug2060]

I wouldn't use anything made by valucraft on my cars ever again.

Valucraft plug wires: Bad after 3 months (developed cracks - caused arcing)
Valucraft Brakes: Noisy and inferior quality (cut up rotors on escort)
Valucraft thermostat: Came apart in thermostat housing

I've had bad luck with Valucraft in the past and suggest all to avoid.

Did you use a Valucraft water pump? If so I would suggest it FAILED. LOL! Just kidding but I would look into it.
You may want to have a look at your head gasket once you are sure there is no trapped air and the pump is circulating. Use a compression tester to check cylinder compression. Each cylinder should be between 156min and 199max PSI. They should all be within 15 PSI of each other (Normally). These little motors wear out faster than most engines but I would put my smart money on the head gasket. It's a common problem but easy to fix in these cars.

Good luck...

[Syberfinder]

Thanks Guys,

The temp is back to normal now. My guess is the radiator had something plugging it up. Don't know if it will go back through again and mess with me but it's all good now. The Water pump was from Schucks and and was what ever brand they carry with a lifetime warranty.

Thanks Again!

[Syberfinder]

Okay, back with the problem again. I took the thermostat out of the system and flushed the radiator once more, I got a small section of an old gasket out of the radiator.

The only time the GEO gets hot is when I make a three mile climb on gravel from the valley floor (170 feet) to my place (800 feet). The radiator seems to have heat well dispersed across it although the far edges seem to be a little cool.

I know the water pump is still working. How do I know if my fan is running slower than it should?

[DOCTORBILL]

1. What are you calling "Hot" ?
.....Does it "boil over" ? If not, don't worry about it.

2. Are you using 50:50 Coolant ?
.....Less than 50:50 coolant can BOIL - whereas, 50:50 or higher won't boil at most engine temps.

3. What altitude are you at ?
.....If you are using mostly water (low % coolant), the water will boil way below 212° F at high altimetertude.

Any engine will heat up when you tax it such as going up a hill at low speed where air flow is low.

4. Does your fan come on when the engine is hot ?

Let the car idle in the driveway and watch the temp gauge.
When the gauge climbs, the fan should go on - if not, your temp switch is bad.

5. Does your fan have the shroud around it? Is the Fan on backward ?

I had an old 56 Triumph TR3 when I was in my 20's which ALWAYS overheated.
No shop could figure out why...sold it to a friend...he found the fan blades were on backwards...
not close enough to the radiator to suck air thru it enough to be efficient.

6. Are your radiator fins full of crap ? Bugs, stones, leaves, dead birds, parts of pedestrians, etc ?

If so, the radiator cannot "radiate" - cannot pass gas - as it were...

I have had to spray water with my garden hose backwards thru my car's radiators in order
to clean out accumulated crap.



THAT helps tremendously !.....plus just picking stuff out with a "radiator comb" available at most auto parts stores.

7. Perhaps it is time for...

A. A new (used) radiator.

B. A new (used) fan motor.

DoctorBill over the Hill

[Syberfinder]

1. It makes a boiling sound only when I drive up to my house at 800 feet on gravel. The temp gauge never goes into the danger zone.

2. I believe the coolant is at least 50/50.

3. At least 800 feet.

4. The fan comes on when the coolant is hot.

5. The fan never had a shroud, this is a very resent development too.

6. The Radiator has no gunk stuck in the fins, it's very clean.

Thanks!

[redpepe]

bill's given a good check list.

a missing shroud is the likely problem. very important to the efficiency.

if the gauge is showing hotter when climbing or working hard, that's appropriate. the temp will show a bit higher even with the fan running sometimes. it will cycle up and down within a range that you will soon recognize. the fan must be able to bring down the temperature from the higher readings when working hard and back to 'normal' when idling or cruising. if the gauge is not going into the red area and it does not stay elevated, then you may be ok as is. keep a close watch.

[DOCTORBILL]

I would check the coolant for percentage - buy a simple coolant hygrometer for $5 - good thing to have anyway.

If you are going up 500 feet in a short time, possibly air is bubbling out of the coolant !
That is quite a pressure change if done quickly....

If you don't have one of these - I would visit your local Pull & Save and get one...




Besides - you hear a "Bubbling sound" w/o any change on the temp gauge and you are going up a gravel road...?

How can you hear bubbling sounds while going up a gravel road?

All you'd hear is engine, road and tire noise.

Maybe strut noise - not coolant noise. Or Tires popping on the larger gravel chunks.

I suspect that you are like me - paranoid about engine sounds....

Any new sound drives me nuts....I worry like some old grandmother.

Stop worrying...be happy!

If your Metro doesn't explode or die - then drive and be happy....grin and hum tunes loudly.

Someone (I think Corvett69) said to turn your radio up so you can't hear all the little noises.

Keeps you from going bonkers. Good advice!

DoctorBill over the Hill