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over heating question

Printed From: West Coast Fieros
Category: Technical Topics Forum
Forum Name: Technical Questions and Discussions
Forum Description: Got a technical question about your fiero? ask it here.
URL: http://www.westcoastfieros.com/forum/forum_posts.asp?TID=1367
Printed Date: 24 November 2024 at 9:36am
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Topic: over heating question
Posted By: jkehoe67
Subject: over heating question
Date Posted: 06 June 2009 at 10:19pm
hey there, my cars been acting right funny, it was over heating and ive replaced the thermostat, but the gauge next to teh voltage thats oil pressure correct? i wil be driving and it go down into the red zone, slowly and if i drove it longer the engine would heat right up to the point the coolant would be boiling in the tank, any suggestions, im thinking the fan isnt turning on but would that effect the oil pressure light or is that another form of reading oil tempature?



Replies:
Posted By: madsod
Date Posted: 07 June 2009 at 8:43am
I'm not a mechanic but I would think that the oil sending switch mounted on the engine could be on its way out. Regarding the coolant, I would check for an air lock in the system, I would open the front hood and let the engine idle, checking if the radiator fan does indeed come on. I just replaced my heater core and I had problems with overheating and blowing off fluid out of my reservoir tank because of an air lock. 

Maybe someone else has better suggestions, good luck..


Posted By: jkehoe67
Date Posted: 07 June 2009 at 4:00pm
well found from canadian tire said it was a burnt out fan, but they want like $250 to fix it, easy enough to do my self would anyone have a cheap fan forsale and is living in the vancouver area?


Posted By: Romeo
Date Posted: 07 June 2009 at 4:06pm
Well, to verify if it's the fan, drive it at highway speeds and see if it still over-heats. If it doesn't, I'd start looking elsewhere for problems. As an added note, how's your coolant levels? If they're constantly declining, or are already low, you've got an issue right there. And don't forget, fill from the thermostat housing when filling, not the radiator cap. Somebody else, like the good doctor, should be able to help you further, but I'd start by narrowing down what the problem is.

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Never shift into reverse without a back-up plan.


Posted By: jkehoe67
Date Posted: 07 June 2009 at 4:23pm
yeah stays cool on the highway and plenty of coolant, they put power to the fan and its dead and that would cause the syptoms


Posted By: Patrick
Date Posted: 07 June 2009 at 8:04pm

Originally posted by Romeo Romeo wrote:

Well, to verify if it's the fan, drive it at highway speeds and see if it still over-heats.

Or disconnect the wire from the sending unit and ground it. Or turn on the A/C if the car is so equipped. The fan should come on.

To be honest though, I'm not sure how a bad fan relay would affect this operation.

 



Posted By: Capt Fiero
Date Posted: 07 June 2009 at 8:38pm

Rad fan is about 20mins to change.   If you have A/C good luck in finding an A/C rad fan as no one wants to give up one of those.   Non A/C Rad fans, I think I have a couple here, 20 bucks is probably fair. 

           As Patrick said, try grounding the sending unit and see if the fan turns on, or turn the A/C button on and see if the fan turns on.  If the fan does not fire up, as I said before, I have a couple non A/C fans kicking around. 

 

Oh on the subject of oil pressure, even an overheating engine should not loose so much oil pressure as to fire the warning light.   Depending on the mileage and condition of your engine, even GM released a tech bulletin that any Fiero engine over 60,000 miles (roughly 100,000kms)  should be running 10w30 instead of 5w30.  On really older engines, I run 20w50 in them.   

      Depending on how mechanically inclined you are, you can install a high volume oil pump, which will help to maintain proper oil pressure.  (Requires dropping the exhaust, starter, front motor mount, then the oil pan)      



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Capt Fiero
88 Fiero GT 5spd V6
Eight Fifty Seven GT V8 5spd.


Posted By: jkehoe67
Date Posted: 07 June 2009 at 11:17pm
well i will test the fan myself tomorrow with a direct current, its a non a/c fan. and it just seemed to drop the hotter it got, on the highway when i just had the engine just above idle it would go to normal but at a stop light it would drop slowly and when i pulled over one time it had looked like steam coming out of the dipstick hold and the dipstick was damn hot, but techs at the shop said fan dosnt work, but for $20 that be great are you in vancouver? as i dont have wheels right now,lol


Posted By: Capt Fiero
Date Posted: 07 June 2009 at 11:22pm

 

       Not exactly, about 20mins drive east of Van.   Surrey to be exact.   We are in North Surrey and there is not much public transit over here.  I have actually never taken the bus, so I couldn't help ya on info though, I just know from a few people that have came over here on the bus and said that it is very limited. 

16908 104th Ave.



-------------
Capt Fiero
88 Fiero GT 5spd V6
Eight Fifty Seven GT V8 5spd.


Posted By: jkehoe67
Date Posted: 07 June 2009 at 11:23pm
im in burnaby at the moment actually, been using the skytrain looking for apartments in downtown, but i will try and find a way there and thanks alot


Posted By: Capt Fiero
Date Posted: 07 June 2009 at 11:35pm

Just give me a few hours notice before you come out.  I'll check and see if I have one here at the house, but I may need to go out to the storage and grab one, or if you want, you can ride out to the storage with me and see if there is anything else you need.  

 



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Capt Fiero
88 Fiero GT 5spd V6
Eight Fifty Seven GT V8 5spd.


Posted By: Romeo
Date Posted: 07 June 2009 at 11:35pm

Take the Skytrain to Surrey Central, then go to Bay 11 and look for the C74 (It's infrequent, so check for times). Ride over the highway until you're on 104. When you see a gas station on your right, ring the little bell and get off. Head back towards the gas station, and go left at the intersection. Dave's house will be on the right. You'll know you're there as there's always at least two Fieros visible beside his house (Based upon my experience).

PS, your fare will be $3.75



-------------
Never shift into reverse without a back-up plan.


Posted By: Patrick
Date Posted: 08 June 2009 at 1:01pm

Originally posted by jkehoe67 jkehoe67 wrote:

hey there, my cars been acting right funny, it was over heating and ive replaced the thermostat... and if i drove it longer the engine would heat right up to the point the coolant would be boiling in the tank

any suggestions, im thinking the fan isnt turning on?

I just want to add that in a properly functioning Fiero cooling system, the rad fan will NOT usually come on at all unless it's a very hot day and the car is in stop and go traffic for an extended period of time.

Keep in mind that in a stock setup from the factory, the Fiero rad fan doesn't come on until 230 F which is pretty hot considering the stock thermostat is is 195 F.

I wonder if your Fiero has other issues such as air in the cooling system (have you "burped" it properly?), partially crushed (blocked) cooling pipes (along the bottom sides of the car), or a water pump with a slipping impeller.

Originally posted by jkehoe67 jkehoe67 wrote:

canadian tire said it was a burnt out fan, but they want like $250 to fix it...

I wouldn't let "mechanics" at Canadian Tire lube the chain on my bicycle.

 



Posted By: jkehoe67
Date Posted: 08 June 2009 at 1:16pm
well my coolant was boiling and no fan lol


Posted By: Patrick
Date Posted: 08 June 2009 at 1:26pm

Originally posted by jkehoe67 jkehoe67 wrote:

well my coolant was boiling and no fan lol

Is/was your coolant a proper 50/50 mix of antifreeze and water or just straight water?

...and, do you have the proper rad cap installed?

Both straight water and lack of proper cooling system pressure would/could result in "boiling" coolant at a lower temperature than normal. (At atmospheric pressure, water will boil at 212 F.)

Originally posted by Patrick Patrick wrote:

Keep in mind that in a stock setup from the factory, the Fiero rad fan doesn't come on until 230 F...

 



Posted By: Capt Fiero
Date Posted: 08 June 2009 at 1:34pm

 

              On the subject of cooling systems.  From personal experience and knowledge from working in the Radiator business years ago.  The best mixture for a Fiero cooling system is.

1 gallon antifreeze

1 12oz bottle of water wetter

roughly 2.5 gallons of distilled water from a grocery store.  You can buy it in 1 gallon jugs for about $3 per gallon.

         Don't use Tap water.  30 years ago, tap water was fine.  However tap water now has chemicals minerals and other crap that was not in it, also 30 years ago, most cars had brass/copper rads with almost no electronics. Now with all the junk in tap water and all the extra electrical stuff, you need to use distilled water.  

     Antifreeze is a HORRID coolant.  The heat transfer of antifreeze is really bad.  The only reason to use it at all is to increase the boiling point and decrease the freezing point of water.   So only use as much as you NEED for your climate.  Which around here is roughly 20% NOT 50%.   I drove my 88GT through Death Valley in August, and in Las Vegas in August.  Temps were 50C on the highway.  I can sit in local stop and go traffic literally for ever and never overheat.   

   It would also be a good idea to remove your front cap, stick your finger down there and feel the coolant tubes, if they feel slimy, or really dirty, you probably have crap in your tubes that is reducing the efficiency of your radiator.   Best bet is to remove the rad take out to be cleaned.  However you can TRY the cooling system flush stuff.  However the flush stuff can in some cases cause more damage that help.  if you have weak seals in your engine, it can actually cause water pump leaks or worst case head gasket issues.  

A cheap and easy way of cleaning it out is to remove the front and rear cap, put a garden hose in the rear, let it run so it flushes out the current stuff, remove the rad drain cock so you get as much of the garden hose water out, then fill with the above mixture and go.    You can also fill it with the tap water, run it for 10 mins, then drain / flush it again. 



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Capt Fiero
88 Fiero GT 5spd V6
Eight Fifty Seven GT V8 5spd.


Posted By: Patrick
Date Posted: 08 June 2009 at 2:14pm

Originally posted by Capt Fiero Capt Fiero wrote:

Antifreeze is a HORRID coolant.  The heat transfer of antifreeze is really bad.  The only reason to use it at all is to increase the boiling point and decrease the freezing point of water.   So only use as much as you NEED for your climate.  Which around here is roughly 20% NOT 50%.

There are also rust inhibitors and water pump lubricants in antifreeze.

Just don't forget though if you plan on visiting a colder location sometime during the winter (or if there's a freak cold spell here) that your protection will be somewhat limited. All it takes is ONE cold night. Ask me how I know....

 



Posted By: Capt Fiero
Date Posted: 08 June 2009 at 2:25pm

 

IIRC and I would have to look it up to be sure.  But 20% antifreeze is good to about -21C  I think the coldest I have ever seen here is -16C the average cold is -10c during the winter. 

However 1 gallon of antifreeze is actully closer to 30% so in either case, you will be fine.



-------------
Capt Fiero
88 Fiero GT 5spd V6
Eight Fifty Seven GT V8 5spd.


Posted By: Patrick
Date Posted: 08 June 2009 at 2:40pm

Found a good article on antifreeze and cooling systems http://www.max-boost.co.uk/max-boost/cooling.htm - Here . It even includes some info on checking coolant condition by using a voltmeter!

Dave, I agree that using a lower percentage of antifreeze than 50/50 will allow a cooling system to run a bit more efficiently when it's hot, but I just wanted anyone reading this thread to be aware that there are indeed tradeoffs, the big one being that their car isn't as well protected under frigid conditions.

 



Posted By: Romeo
Date Posted: 08 June 2009 at 3:24pm
Oh right, because coolant and water have a different conductivity than one another, so in testing voltage drop across a set distance, you could tell how much of each is in the mix due to the difference in resistence (Which is what governs voltage drop). That's actually pretty cool.

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Never shift into reverse without a back-up plan.


Posted By: jkehoe67
Date Posted: 08 June 2009 at 7:57pm
ok i about to bang my head off something, fan works great tested the new one and thanks alot, but its still having a prob getting hot, the oil pressure gauge will drop into the red very slowly when driving and when sitting, and the dipstick gets to hot to even touch, and think its straight coolant


Posted By: Bobz0r
Date Posted: 08 June 2009 at 8:06pm
How is the oil level. Low oil can cause low pressure at idle and when cornering, and is a VERY bad thing.


Posted By: jkehoe67
Date Posted: 08 June 2009 at 8:19pm
no i checked the oil its on the dot, just the oil itsself get so hot, can something be clogging the coolant from circulating, anyway to check it?


Posted By: Bobz0r
Date Posted: 08 June 2009 at 9:12pm

Has the oil filter been changed recently? It could be causeing a problem, but I've never heard of it doing anything like what you're describing.

 

Also, does the engine burn or leak at all? Those could be a sign of low pressure once the motor warms up. Have you tried a thicker oil? (It would only be a temporary fix)



Posted By: Romeo
Date Posted: 08 June 2009 at 9:15pm
Is the water pump physically moving the water? If you have air in the system, it will cause a bubble right before the water pump which will block water/coolant from entering it, and thus the engine. This problem will also be more severe at low RPM (See: Idle) as the pump wont be spinning as much as it does at higher RPMs, such as those on the highway.

-------------
Never shift into reverse without a back-up plan.


Posted By: jkehoe67
Date Posted: 08 June 2009 at 9:19pm
how would i check that?


Posted By: Patrick
Date Posted: 08 June 2009 at 9:24pm

Originally posted by jkehoe67 jkehoe67 wrote:

can something be clogging the coolant from circulating

Did you see my earlier post?

Originally posted by Patrick Patrick wrote:

I wonder if your Fiero has other issues such as air in the cooling system (have you "burped" it properly?), partially crushed (blocked) cooling pipes (along the bottom sides of the car), or a water pump with a slipping impeller.

 



Posted By: Capt Fiero
Date Posted: 08 June 2009 at 9:32pm

Take your hand and feel the coolant pipes along the bottom of the car and feel for any crushed areas in the pipes.      To get a rough idea if the water pump is working.  Remove the rear coolant cap, fire up the engine, water should SHOOT out of the filler neck. If it does not move much at all, the pump is shot.

 



-------------
Capt Fiero
88 Fiero GT 5spd V6
Eight Fifty Seven GT V8 5spd.


Posted By: jkehoe67
Date Posted: 09 June 2009 at 7:43pm
is there anyone in burnaby or so that has a personal shop? id like to get this fixed but most places i heard dont even know what to do with a fiero and charge a fortune, 


Posted By: Capt Fiero
Date Posted: 09 June 2009 at 8:15pm

 

I am sure the good doctor could squeeze you in, even if it is just to confirm what the problem is.   Not sure how much time he has, as he is swamped with work right now.   He has a small home shop in West Surrey / North Delta.   A few blocks from Scott road in Surrey.    Drop him a PM and I am sure he can help ya.



-------------
Capt Fiero
88 Fiero GT 5spd V6
Eight Fifty Seven GT V8 5spd.


Posted By: Dr.Fiero
Date Posted: 09 June 2009 at 9:54pm
And as with most Dr's....  I don't usually make house calls, so you'll have to make it over here.  




Posted By: jkehoe67
Date Posted: 11 June 2009 at 12:22pm
well just got great news from my job so gonna sell, for $1500 firm, gotta go the sell threads and post pics, if anyones interested prob something small for this over heat thing, but got new fan switch but cant install cause no tools at the moment



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