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Running without a thermostat? by BabyEating Dingo
Started on: 04-28-2014 09:58 PM
Replies: 23 (612 views)
Last post by: rogergarrison on 07-13-2014 06:48 PM
BabyEating Dingo
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Report this Post04-28-2014 09:58 PM Click Here to See the Profile for BabyEating DingoSend a Private Message to BabyEating DingoEdit/Delete MessageReply w/QuoteDirect Link to This Post
Long story short, while troubleshooting engine overheating problems, I removed the thermostat cap to discover that the PO sold me the car without a thermostat! So that brings up a few questions for yall who know more than I do...

1. I've run the car for about 200 miles without a thermostat. Could that hurt anything on the car?

2. The PO cut a lot of corners trying to get this car to run (then did a good job covering it all up so I didn't know). Would running the car without the thermostat actually help with the overheating issue?

3. There are a lot of thermostats for the Fiero with different temperature ratings that I can find, 185, 195, 160. Is there any advantage to running any specific one?
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Csjag
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Report this Post04-28-2014 10:17 PM Click Here to See the Profile for CsjagClick Here to Email CsjagSend a Private Message to CsjagEdit/Delete MessageReply w/QuoteDirect Link to This Post
Do you have the 4 or 6 cylinder?
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BabyEating Dingo
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Report this Post04-28-2014 10:19 PM Click Here to See the Profile for BabyEating DingoSend a Private Message to BabyEating DingoEdit/Delete MessageReply w/QuoteDirect Link to This Post
6 cylinder GT.
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notaguru
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Report this Post04-28-2014 10:32 PM Click Here to See the Profile for notaguruClick Here to visit notaguru's HomePageClick Here to Email notaguruSend a Private Message to notaguruEdit/Delete MessageReply w/QuoteDirect Link to This Post
Let a building full of GM engineers address your problem: they designed the system to run with a 195deg thermostat, and it works well.

Absence of a thermostat won't hurt the car, but it is in there to quickly get the system to its design operating temp and then keep it there.

If there's an overheating problem in this car, it's somewhere else. In your case, consider the possibility of an air block in that complex remote-cooling configuration. Bleeding air from the system is a non-trivial exercise.
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Report this Post04-28-2014 10:45 PM Click Here to See the Profile for CsjagClick Here to Email CsjagSend a Private Message to CsjagEdit/Delete MessageReply w/QuoteDirect Link to This Post
Yes the car is designed for a 195 degree thermostat. One change that has proven beneficial for a lot of people is Rodney Dickman's Fiero parts lower temperature range fan switch that keeps the engine temp within a narrower band instead of having it jump to 240 degrees before the radiator fan kicks on.
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Report this Post04-28-2014 10:51 PM Click Here to See the Profile for olejoedadClick Here to Email olejoedadSend a Private Message to olejoedadEdit/Delete MessageReply w/QuoteDirect Link to This Post
Install a 195 stat, drive it, tell us what happens......
We are here to help....
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Blacktree
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Report this Post04-29-2014 12:11 AM Click Here to See the Profile for BlacktreeClick Here to visit Blacktree's HomePageClick Here to Email BlacktreeSend a Private Message to BlacktreeEdit/Delete MessageReply w/QuoteDirect Link to This Post
Removing the thermostat shouldn't cause any damage to the engine. But it doesn't help, either. People sometimes remove the thermostat as a band-aid fix for other problems in the cooling system. But that doesn't actually fix anything. It's just a lazy man's way of postponing a repair until later.

An automobile engine runs best when its operating temperature is kept within a small range. The Fiero engines are happy at around 190-215 degrees F. So a 195F thermostat will work fine. And as mentioned above, Rodney Dickman sells a 210F fan switch.

If the engine still overheats after getting a good thermostat and fan switch installed, then the other parts of the cooling system need to be checked.

Best of luck.
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Report this Post04-29-2014 08:17 AM Click Here to See the Profile for fierofoolClick Here to visit fierofool's HomePageClick Here to Email fierofoolSend a Private Message to fierofoolEdit/Delete MessageReply w/QuoteDirect Link to This Post
Often times the fuel mileage suffers with the lower temp thermostats or when run without a thermostat. The engine doesn't reach operating temperature and the coolant temperature sensor is telling the ECM that the engine is cold, keeping it in open loop with a richer air fuel mixture.
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84fiero123
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Report this Post04-29-2014 11:07 AM Click Here to See the Profile for 84fiero123Click Here to Email 84fiero123Send a Private Message to 84fiero123Edit/Delete MessageReply w/QuoteDirect Link to This Post
You may have a crushed coolant pipe under the body, a common problem with these cars as it runs the full length of the underside of the car. I said may now, it could be someone put some type of anti leak in the radiator as well. that crap plugs up everything and can cause over heating issues. a flush and fill of the coolant system could tell you if that is the problem, maybe.

Steve

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theogre
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Report this Post04-29-2014 11:44 AM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post
Do damage? unlikely.
Overheat w/ Tstat? Likely bad Tstat or removing hides other issues.
Under heat engine? Yes is a real problem and often causes Poor MPG.
No "Close Loop" operation? Depend on ECM programing. Some uses ECT and other don't, even using 1 wire O2 sensor.

Get new Tstat and fix whatever problems.
See my Cave, Thermostat and rest of section.

Open vs. Close Loop Modes
Close Loop mainly needs O2 sensor to heat up to work right. Many ECM/PCM will go into Close Loop as soon as it gets good O2 sensor output. Others use ECT and O2 to set close loop mode.
You would need ECM scan tool to really see if ECM cares about ECT or not in Close Loop mode.
Example: 87 DIS Duke will go Close Loop very fast even engine is freezing. Takes 30 sec - 2 minutes in the winter for O2 to warm up and sends a signal.

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Report this Post04-29-2014 12:15 PM Click Here to See the Profile for tebaileyClick Here to Email tebaileySend a Private Message to tebaileyEdit/Delete MessageReply w/QuoteDirect Link to This Post
I agree with olejoedad, put in a tstat and try that first.
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Report this Post04-29-2014 01:33 PM Click Here to See the Profile for bjc 350Send a Private Message to bjc 350Edit/Delete MessageReply w/QuoteDirect Link to This Post
You don't indicate whether your car is a stick or auto. I had an automatic that would not keep the torque converter locked up at highway speeds. I checked the thermostat, and it was 160 degrees. I changed it to 180 degree with Dickmans low temp fan switch , and the transmission worked correctly after the changes. In retrospect, the 195 degree would have been an even better bet.
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Report this Post04-29-2014 05:03 PM Click Here to See the Profile for rogergarrisonClick Here to Email rogergarrisonSend a Private Message to rogergarrisonEdit/Delete MessageReply w/QuoteDirect Link to This Post
Running without one does cause some engines to get hot spots in the block and heads because the water goes the path of least resistance..so it dont circulate as well in some smaller ports. It can damage an engine in EXTREME cases, but unlikely you hurt anything. The thermostat provides SOME resistance so its just not free flowing, and moves thru all the ports.
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Report this Post04-29-2014 05:03 PM Click Here to See the Profile for fierosoundClick Here to visit fierosound's HomePageClick Here to Email fierosoundSend a Private Message to fierosoundEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by BabyEating Dingo:

2. The PO cut a lot of corners trying to get this car to run (then did a good job covering it all up so I didn't know).
Would running the car without the thermostat actually help with the overheating issue?



Water pump may not be working 100%.
Happens if the impeller comes loose on the shaft.

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BabyEating Dingo
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Report this Post04-29-2014 07:39 PM Click Here to See the Profile for BabyEating DingoSend a Private Message to BabyEating DingoEdit/Delete MessageReply w/QuoteDirect Link to This Post
I put in a new 195º thermostat and burped the system today. After running the engine for only a few minutes, the temperature gauge on the dash climbed extremely fast; it reached 230º with no sign of slowing down before I shut it off. I checked the air coming off of the radiator/fan, it didn't feel nearly hot enough for the engine to be at such a high temperature. Putting my hand near the block sure feels pretty darn hot though.

I let the engine cool down and ran it without the thermostat again, to compare. It still started to overheat, though it took significantly longer than it did with the thermostat in.

I also tested running the engine for a few seconds without the thermostat housing cap on - coolant gushed out, so the water pump seems to be working, though I don't know exactly how well.

The undercarriage coolant line on the driver's side has a small dent in it. Possible culprit? Also possible the radiator is clogged. This would explain why the air coming off the radiator isn't proportionally hot. Yet, it's also possible the water pump isn't reaching a high enough pressure to push the hot coolant through the radiator while the thermostat is in.

Any ideas on how I can test this further?

Edit: It's a 1987 V6 GT automatic. The PO let this thing sit for a quite a while, and it looks like basic maintenance wasn't regularly performed. A few days ago I replaced the alternator, both belts, rear calipers, and brake hoses. With the exception of the serpentine, all of the parts were original with the car. The brake hoses were so old and dry they were cracking and falling apart in chunks as I removed them. I'm willing to bet everything in the coolant system is around 30 years old, too.

[This message has been edited by BabyEating Dingo (edited 04-29-2014).]

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Csjag
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Report this Post04-29-2014 07:52 PM Click Here to See the Profile for CsjagClick Here to Email CsjagSend a Private Message to CsjagEdit/Delete MessageReply w/QuoteDirect Link to This Post
Sounds like an air pocket but if you think the radiator is clogged I would take it to a shop that specializes in radiators and have them test it for flow and pressure holding. I don't think a small dent in the coolant tube would be enough to cause what you describe. Jack up the back of the car and take off the radiator cap then add coolant thru the filler neck in the back and a quart or so flow out of the top of the radiator, that will remove air pockets.
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Report this Post04-30-2014 10:37 AM Click Here to See the Profile for 2.5Send a Private Message to 2.5Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by BabyEating Dingo:

I put in a new 195º thermostat and burped the system today. After running the engine for only a few minutes, the temperature gauge on the dash climbed extremely fast; it reached 230º with no sign of slowing down before I shut it off. I checked the air coming off of the radiator/fan, it didn't feel nearly hot enough for the engine to be at such a high temperature. Putting my hand near the block sure feels pretty darn hot though.

I let the engine cool down and ran it without the thermostat again, to compare. It still started to overheat, though it took significantly longer than it did with the thermostat in.

I also tested running the engine for a few seconds without the thermostat housing cap on - coolant gushed out, so the water pump seems to be working, though I don't know exactly how well.

The undercarriage coolant line on the driver's side has a small dent in it. Possible culprit? Also possible the radiator is clogged. This would explain why the air coming off the radiator isn't proportionally hot. Yet, it's also possible the water pump isn't reaching a high enough pressure to push the hot coolant through the radiator while the thermostat is in.

Any ideas on how I can test this further?

Edit: It's a 1987 V6 GT automatic. The PO let this thing sit for a quite a while, and it looks like basic maintenance wasn't regularly performed. A few days ago I replaced the alternator, both belts, rear calipers, and brake hoses. With the exception of the serpentine, all of the parts were original with the car. The brake hoses were so old and dry they were cracking and falling apart in chunks as I removed them. I'm willing to bet everything in the coolant system is around 30 years old, too.



It wont over heat until over 235 degrees, the fan kicks on at 235. From what you described the temps were still normal so far.
A small dent probly wont hurt, you could post pics.

[This message has been edited by 2.5 (edited 04-30-2014).]

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olejoedad
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Report this Post04-30-2014 10:44 AM Click Here to See the Profile for olejoedadClick Here to Email olejoedadSend a Private Message to olejoedadEdit/Delete MessageReply w/QuoteDirect Link to This Post
Sounds like an air pocket. Remove t stat, loosen front cap until fluid runs out, retighten front cap, fill engine at tstat, install cap, run for 15-30 seconds, take cap off, fill, repeat until level stays good. If problem persists, look for blockages or soft water pump inlet hose.
If the pump is gushing out of tstat housing, flow is good, it is not a pressure system until temp builds with cap on, it is a flow system.

[This message has been edited by olejoedad (edited 04-30-2014).]

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Report this Post04-30-2014 01:19 PM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by BabyEating Dingo:
The undercarriage coolant line on the driver's side has a small dent in it. Possible culprit? Also possible the radiator is clogged. This would explain why the air coming off the radiator isn't proportionally hot. Yet, it's also possible the water pump isn't reaching a high enough pressure to push the hot coolant through the radiator while the thermostat is in.

Small hit you can see...
small hit on bottom often a sign bent tube.
See my Cave, Crushed Pipe
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BabyEating Dingo
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Report this Post07-13-2014 04:49 PM Click Here to See the Profile for BabyEating DingoSend a Private Message to BabyEating DingoEdit/Delete MessageReply w/QuoteDirect Link to This Post
So it turns out I misled yall about the dented coolant line... I remembered it being a lot smaller than it actually was.

Here's a picture of the driver side, and the passenger side. It's a damn disaster. The PO must have crushed them both with a jack, and only bothered to repair the passenger side by cutting off the damaged section and clamping a hose on it.

I'm just going to do that sort of fix. Cut the bad section off and put a hose on it, unless the collective Fiero hive has a better idea. What diameter hose is needed? Is it easier to take off the pipe to work on it, or can it be done on the car?


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Csjag
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Report this Post07-13-2014 05:18 PM Click Here to See the Profile for CsjagClick Here to Email CsjagSend a Private Message to CsjagEdit/Delete MessageReply w/QuoteDirect Link to This Post
From the pics it looks like you may be able to cut out the section with a short blade on a sawsall but be very careful, or else use a small hacksaw. I would take the cutout section with you to the parts store to be the right size hose but I wonder if the tubing is strong enough to clamp down on without bending.
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Report this Post07-13-2014 05:32 PM Click Here to See the Profile for rogergarrisonClick Here to Email rogergarrisonSend a Private Message to rogergarrisonEdit/Delete MessageReply w/QuoteDirect Link to This Post
With OEM thermostat and fan switch, the fan dont even come on at all till its 234*. Its the same on Corvettes. Even after you replace the tubes, Id use Rodneys lower fan switch so it comes on a lot sooner.

You could put shorter hoses at the ends and run hot water PVC pipe to replace the tubes. They handle boiling water, so they would be fine. At home improvement stores like Home Depot, you can also buy galvanzied electrical conduit. I pay less than $10 for 10 feet ( 1/8 X 1-1/4") of it. I just used it to make a 20' tailpipe for a generator exhaust.
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Report this Post07-13-2014 05:50 PM Click Here to See the Profile for larry mimbsClick Here to Email larry mimbsSend a Private Message to larry mimbsEdit/Delete MessageReply w/QuoteDirect Link to This Post
Don't ever use conduit for a pressure system. Most of it has a seam that is not water tight.
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rogergarrison
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Report this Post07-13-2014 06:48 PM Click Here to See the Profile for rogergarrisonClick Here to Email rogergarrisonSend a Private Message to rogergarrisonEdit/Delete MessageReply w/QuoteDirect Link to This Post
Didnt know that. I just looked good at a piece I cut off and cant find any kind of a seam in it though....Maybe there are different kinds ? Maybe with a seam, you couldnt use it for high pressure, but a car cooling system is only 14-16 pnds max.

[This message has been edited by rogergarrison (edited 07-13-2014).]

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