Blown head gasket?
#1
Member
Thread Starter
Join Date: May 2014
Location: Alpine
Posts: 448
Likes: 0
Received 0 Likes
on
0 Posts
Car: 86 Trans Am
Engine: 305 LB9
Transmission: 700r4
Blown head gasket?
I've had ongoing cooling issues on the highway. Airdam in tact and no blockages. On the highway I nearly reached 3/4 on temp. I was past 220. I pulled over and turned on the heat. This was with ac on. Kept driving once it cooled to 220 and it would slowly heat up again. Once I got home I popped the hood and coolant started coming out of the overflow. Brand new cooling system. If not a head gasket, possible thermostat?
It drove just fine and wasn't sluggish. It cools wayyyy down on in town driving. No bad driving issues in town either hot or cold. Today was especially hot too around 100 degrees.
As I said in the other topic I am an EMT and need my vehicle for response to the station when there's a call so I need to try and keep its downtime low so I want to start with the thermostat.
Any advice is greatly appreciated
It drove just fine and wasn't sluggish. It cools wayyyy down on in town driving. No bad driving issues in town either hot or cold. Today was especially hot too around 100 degrees.
As I said in the other topic I am an EMT and need my vehicle for response to the station when there's a call so I need to try and keep its downtime low so I want to start with the thermostat.
Any advice is greatly appreciated
#2
Member
Thread Starter
Join Date: May 2014
Location: Alpine
Posts: 448
Likes: 0
Received 0 Likes
on
0 Posts
Car: 86 Trans Am
Engine: 305 LB9
Transmission: 700r4
Re: Blown head gasket?
Also I forgot to add that I don't believe the temp sensor is bad because I get bad gas mileage as soon as it starts getting hotter
#3
Supreme Member
iTrader: (2)
Join Date: Jan 2005
Location: S. UTAH
Posts: 1,244
Likes: 0
Received 162 Likes
on
134 Posts
Car: 1989 IROC-Z 305 LB9 AT Convertible
Engine: LB9 305
Transmission: AT
Re: Blown head gasket?
Sounds like a "dye test" (or other test) for combustion in the coolant is in order. This to look for head gasket, cracked head problem.
Last time I was hurting for a reliable car, I leased a 2016 Chev Cruze for $92 mo. w/ $1000 down, to alleviate the stress. (There now running a little more).
Last time I was hurting for a reliable car, I leased a 2016 Chev Cruze for $92 mo. w/ $1000 down, to alleviate the stress. (There now running a little more).
#4
Supreme Member
iTrader: (7)
Join Date: May 2004
Location: Lexington, SC
Posts: 5,291
Likes: 0
Received 58 Likes
on
52 Posts
Car: 1987 SC/1985 TA
Engine: 350/vortec/fitech
Transmission: T56
Axle/Gears: 3.27 9-bolt
Re: Blown head gasket?
try a new radiator cap before going further.
then let it idle in the driveway. it should heat up until the fan comes on, cool down until the fan turns off then repeat until it runs out of gas
then let it idle in the driveway. it should heat up until the fan comes on, cool down until the fan turns off then repeat until it runs out of gas
#5
Member
Thread Starter
Join Date: May 2014
Location: Alpine
Posts: 448
Likes: 0
Received 0 Likes
on
0 Posts
Car: 86 Trans Am
Engine: 305 LB9
Transmission: 700r4
Re: Blown head gasket?
The car does just fine idling by the way. I sat outside in the heat with ac waiting on a friend and it barely touched middle and went down. In town it is fine around 30 or so. But when you start holding rpms like highway or even about 45-50 it starts having some issues
Once I try the rad cap I will do a compression test. Been holding off because I don't want to know if it is a head gasket or not lol. I've only done a compression for leaks, how would I do one for a head gasket?
#6
Member
Thread Starter
Join Date: May 2014
Location: Alpine
Posts: 448
Likes: 0
Received 0 Likes
on
0 Posts
Car: 86 Trans Am
Engine: 305 LB9
Transmission: 700r4
Re: Blown head gasket?
Unfortunately I haven't had a break to do any work. I did notice tonight this vacuum line was unhooked. Also when the car gets over half the overfill goes all the way to the top and stops?
Unhooked line
The round portion on top is where it connected to
UPDATE: Purchased a 160 degree fail safe - says when it overheats it stays open permitting coolant flow which i suspect may be my issue.
Purchased the gasket. As well as some strong coolant. Anyone remove the tstat on tpi without removing the intake? My problem has got worse as it will overheat during idle. No coolant in oil or vice versa
Unhooked line
The round portion on top is where it connected to
UPDATE: Purchased a 160 degree fail safe - says when it overheats it stays open permitting coolant flow which i suspect may be my issue.
Purchased the gasket. As well as some strong coolant. Anyone remove the tstat on tpi without removing the intake? My problem has got worse as it will overheat during idle. No coolant in oil or vice versa
Last edited by apie2546; 06-12-2016 at 04:44 PM.
#7
Member
Thread Starter
Join Date: May 2014
Location: Alpine
Posts: 448
Likes: 0
Received 0 Likes
on
0 Posts
Car: 86 Trans Am
Engine: 305 LB9
Transmission: 700r4
Re: Blown head gasket?
Pulled over when I started to overheat and the fan was not on. This explains in town overheating, but on the highway?
Trending Topics
#8
Supreme Member
iTrader: (5)
Join Date: Nov 2010
Location: Mantua NJ
Posts: 5,827
Received 64 Likes
on
57 Posts
Car: 1 Owner 1986 TA with a WS6 package
Engine: 5.0 EFI
Transmission: THM700R4
Axle/Gears: 277 Posi Speedo
Re: Blown head gasket?
Is your air deflector in place?? if that's not there,that would cause the overheating while your driving!.
#9
Member
Thread Starter
Join Date: May 2014
Location: Alpine
Posts: 448
Likes: 0
Received 0 Likes
on
0 Posts
Car: 86 Trans Am
Engine: 305 LB9
Transmission: 700r4
#10
Supreme Member
iTrader: (7)
Join Date: May 2004
Location: Lexington, SC
Posts: 5,291
Likes: 0
Received 58 Likes
on
52 Posts
Car: 1987 SC/1985 TA
Engine: 350/vortec/fitech
Transmission: T56
Axle/Gears: 3.27 9-bolt
Re: Blown head gasket?
a different t-stat won't solve an overheat issue unless the old one is stuck closed.
try a radiator cap first
fix your fan
try a radiator cap first
fix your fan
#11
Member
Thread Starter
Join Date: May 2014
Location: Alpine
Posts: 448
Likes: 0
Received 0 Likes
on
0 Posts
Car: 86 Trans Am
Engine: 305 LB9
Transmission: 700r4
Re: Blown head gasket?
The radiator cap didn't fix it sadly. The fan is under warranty. Had to respond in bad weather and I think some water messed it up
#12
Member
Thread Starter
Join Date: May 2014
Location: Alpine
Posts: 448
Likes: 0
Received 0 Likes
on
0 Posts
Car: 86 Trans Am
Engine: 305 LB9
Transmission: 700r4
Re: Blown head gasket?
Will have an answer tomorrow if the fan fixes all of it. Would a bad cooling fan cause the ac to get warm at idle?
#14
Member
Thread Starter
Join Date: May 2014
Location: Alpine
Posts: 448
Likes: 0
Received 0 Likes
on
0 Posts
Car: 86 Trans Am
Engine: 305 LB9
Transmission: 700r4
Re: Blown head gasket?
Update
Fan was replaced, motor was bad. Didn't turn on because relay was burned out and the pigtail wires were frayed and shorted
Fan was replaced, motor was bad. Didn't turn on because relay was burned out and the pigtail wires were frayed and shorted
#16
Member
Thread Starter
Join Date: May 2014
Location: Alpine
Posts: 448
Likes: 0
Received 0 Likes
on
0 Posts
Car: 86 Trans Am
Engine: 305 LB9
Transmission: 700r4
#17
Supreme Member
iTrader: (7)
Join Date: May 2004
Location: Lexington, SC
Posts: 5,291
Likes: 0
Received 58 Likes
on
52 Posts
Car: 1987 SC/1985 TA
Engine: 350/vortec/fitech
Transmission: T56
Axle/Gears: 3.27 9-bolt
Re: Blown head gasket?
for an 86 the fan is likely engaged by a switch within the AC head and runs continuously while the AC is on.
running on the highway won't hurt it
running on the highway won't hurt it
#18
Member
Thread Starter
Join Date: May 2014
Location: Alpine
Posts: 448
Likes: 0
Received 0 Likes
on
0 Posts
Car: 86 Trans Am
Engine: 305 LB9
Transmission: 700r4
#20
Member
Thread Starter
Join Date: May 2014
Location: Alpine
Posts: 448
Likes: 0
Received 0 Likes
on
0 Posts
Car: 86 Trans Am
Engine: 305 LB9
Transmission: 700r4
Re: Blown head gasket?
Well the repair continues.
The relay, new fan motor and pigtail still does not activate the fan to come on. What else could be missing?
The relay, new fan motor and pigtail still does not activate the fan to come on. What else could be missing?
#22
Member
Thread Starter
Join Date: May 2014
Location: Alpine
Posts: 448
Likes: 0
Received 0 Likes
on
0 Posts
Car: 86 Trans Am
Engine: 305 LB9
Transmission: 700r4
Re: Blown head gasket?
Not yet, I assumed since it doesn't come on when the ac comes on something in the circuit is wrong
#23
Supreme Member
iTrader: (5)
Join Date: Nov 2010
Location: Mantua NJ
Posts: 5,827
Received 64 Likes
on
57 Posts
Car: 1 Owner 1986 TA with a WS6 package
Engine: 5.0 EFI
Transmission: THM700R4
Axle/Gears: 277 Posi Speedo
Re: Blown head gasket?
http://contentinfo.autozone.com/znet.../TU66/image/2/
You almost replaced everything else,I would change the AC pressure switch and the coolant temperature switch for now there's nothing else left to change,unless you got a bad fan motor from your supplier.
This would drive me
You almost replaced everything else,I would change the AC pressure switch and the coolant temperature switch for now there's nothing else left to change,unless you got a bad fan motor from your supplier.
This would drive me
#24
Member
Thread Starter
Join Date: May 2014
Location: Alpine
Posts: 448
Likes: 0
Received 0 Likes
on
0 Posts
Car: 86 Trans Am
Engine: 305 LB9
Transmission: 700r4
Re: Blown head gasket?
I believe the shop that put it in said when they manually powered it, it came on but I will double check. Anyway to temporarily have it come on when the cars on? I read about grounding it to another circuit but I don't have any idea which wire to ground or where to ground it. This will help since I need a quick fix and I drive with ac all day anyway so the fan would normally be running until I have more diagnosis time
#25
Supreme Member
iTrader: (5)
Join Date: Nov 2010
Location: Mantua NJ
Posts: 5,827
Received 64 Likes
on
57 Posts
Car: 1 Owner 1986 TA with a WS6 package
Engine: 5.0 EFI
Transmission: THM700R4
Axle/Gears: 277 Posi Speedo
Re: Blown head gasket?
No, I don't were to ground it either. Me personally, I would take the car to my mechanic for something like that.
#26
Member
Thread Starter
Join Date: May 2014
Location: Alpine
Posts: 448
Likes: 0
Received 0 Likes
on
0 Posts
Car: 86 Trans Am
Engine: 305 LB9
Transmission: 700r4
Re: Blown head gasket?
Sadly this entire week its been at my mechanic. They've had a hell of a time. They replaced the blown relay and wiring. I got it back today because this unfortunatly is the last day this month I can take off. So hopefully I can figure out a fix
#27
Member
Thread Starter
Join Date: May 2014
Location: Alpine
Posts: 448
Likes: 0
Received 0 Likes
on
0 Posts
Car: 86 Trans Am
Engine: 305 LB9
Transmission: 700r4
Re: Blown head gasket?
Just so we are all on the same page:
Relay, fan motor, and pigtail was replaced.
Fans do not come on period, even if ac is on. Mechanic said all wires and fuses are getting power but it isn't starting the fan but they can jump the fan? Any fuse I can check. I checked the relay connector. Looks all okay. Not sure how to pull the wires out of the connector to ground green and white wire
Relay, fan motor, and pigtail was replaced.
Fans do not come on period, even if ac is on. Mechanic said all wires and fuses are getting power but it isn't starting the fan but they can jump the fan? Any fuse I can check. I checked the relay connector. Looks all okay. Not sure how to pull the wires out of the connector to ground green and white wire
#28
Supreme Member
Re: Blown head gasket?
i'd change the coolant temp sensor/switch as suggested.
if that doesnt work, maybe a kit like this would work for ya?
https://www.summitracing.com/parts/der-16759/overview/
if that doesnt work, maybe a kit like this would work for ya?
https://www.summitracing.com/parts/der-16759/overview/
#29
Supreme Member
Join Date: May 2015
Location: Florida
Posts: 1,712
Received 241 Likes
on
186 Posts
Car: 1991 Z28
Engine: 305 TPI
Transmission: 700R4
Axle/Gears: 3:42 Auburn
Re: Blown head gasket?
Just so we are all on the same page:
Relay, fan motor, and pigtail was replaced.
Fans do not come on period, even if ac is on. Mechanic said all wires and fuses are getting power but it isn't starting the fan but they can jump the fan? Any fuse I can check. I checked the relay connector. Looks all okay. Not sure how to pull the wires out of the connector to ground green and white wire
Relay, fan motor, and pigtail was replaced.
Fans do not come on period, even if ac is on. Mechanic said all wires and fuses are getting power but it isn't starting the fan but they can jump the fan? Any fuse I can check. I checked the relay connector. Looks all okay. Not sure how to pull the wires out of the connector to ground green and white wire
Check the power to and from the HVAC head. There is a switch in there that goes bad as it is a rotating contact switch. This is what sends the power to the fan relay when you turn on the a/c. this just controls the a/c part.
#30
Member
Thread Starter
Join Date: May 2014
Location: Alpine
Posts: 448
Likes: 0
Received 0 Likes
on
0 Posts
Car: 86 Trans Am
Engine: 305 LB9
Transmission: 700r4
Re: Blown head gasket?
Changed coolant temp and fan switches. No change, where is the fusible link located?
#31
Supreme Member
iTrader: (5)
Join Date: Nov 2010
Location: Mantua NJ
Posts: 5,827
Received 64 Likes
on
57 Posts
Car: 1 Owner 1986 TA with a WS6 package
Engine: 5.0 EFI
Transmission: THM700R4
Axle/Gears: 277 Posi Speedo
Re: Blown head gasket?
IIRC,it's the thin Red wire coming off the battery terminal,There's the big red wire(starter) and a Black and Red wire that goes to some sort of junction.feel if the red wire has a break in it right after the junction.(This is all in the battery area.)
it should be just under where the ground cable is in this pic,
it should be just under where the ground cable is in this pic,
Last edited by mantaguy; 06-30-2016 at 07:48 PM.
#32
Member
Thread Starter
Join Date: May 2014
Location: Alpine
Posts: 448
Likes: 0
Received 0 Likes
on
0 Posts
Car: 86 Trans Am
Engine: 305 LB9
Transmission: 700r4
Re: Blown head gasket?
Hmm that's the part they replaced. Looks like I need to double check the wiring diagram to see what else may be causing an issue
#33
Junior Member
Join Date: Jan 2016
Location: Newaygo, MI
Posts: 30
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1990 Iroc Z
Engine: 5.7
Transmission: 700R4 going to T56
Axle/Gears: Not sure yet
Re: Blown head gasket?
Did you put that 165 stat in? How many fans do you have. Mine is a 90 and has 2 fans. The primary is activated by the ecm. The ecm has programmed parameters that keeps it from turning on the primary fan until it hits 195 degrees. So if you put a lower temp tstat in, your primary fan still won't kick on till 195. If you did put the lower temp in. Was it before you changed the temp sensor? Also if you do have a secondary fan, what temp is the sensor on that. Stock doesn't come on til like 245 I think.
#34
Member
Thread Starter
Join Date: May 2014
Location: Alpine
Posts: 448
Likes: 0
Received 0 Likes
on
0 Posts
Car: 86 Trans Am
Engine: 305 LB9
Transmission: 700r4
Re: Blown head gasket?
No the original t stat is still in it. And it is an 86 with single fan. From what I remember the fan came on around 220. It got up to 240 the other day and nothing
#35
Junior Member
Join Date: Jan 2016
Location: Newaygo, MI
Posts: 30
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1990 Iroc Z
Engine: 5.7
Transmission: 700R4 going to T56
Axle/Gears: Not sure yet
Re: Blown head gasket?
I wonder how it's wired. I hate adding toggle switches..... Maybe flushing the system..... Maybe your ecm needs more than the information it gets from just the coolant temp sensor which is different than the coolant temp sending unit. But your fan has it's own sensor which is not controlled by the ecm. Ecu. Sorry. If the fan is wired correctly, it has it's own sensor. If that doesn't make it turn on, I'm not sure. Unless if it has it's own sensor but it's wired to your computer and that makes it fail???
I'll do some digging. At least you can drive it for now. Good luck!!!!!
I'll do some digging. At least you can drive it for now. Good luck!!!!!
#36
Member
Thread Starter
Join Date: May 2014
Location: Alpine
Posts: 448
Likes: 0
Received 0 Likes
on
0 Posts
Car: 86 Trans Am
Engine: 305 LB9
Transmission: 700r4
Re: Blown head gasket?
I do have a update. Checked relay today with car running and ac on. The relay was grounded because I got sparks on the ground wire. I had no power from any of the other terminals. I believe there is three to four pins. In any regard, one is empty. None had power but it was grounded. I tested these by pulling the terminal from the relay checking the pins
#37
Member
Thread Starter
Join Date: May 2014
Location: Alpine
Posts: 448
Likes: 0
Received 0 Likes
on
0 Posts
Car: 86 Trans Am
Engine: 305 LB9
Transmission: 700r4
Re: Blown head gasket?
Turns out the computer wasn't supplying ground. So I grounded it when the car comes on
#38
Junior Member
Join Date: May 2016
Posts: 4
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1986 Camaro Iroc Z/28
Engine: 305 TPI
Transmission: 700r4
Re: Blown head gasket?
My 86 Iroc has been having some overheating issues. I just replaced the radiator with an aluminum 3 core and the thermostat as well. I drive the car for 30 minutes and it's fine, but then it starts to overheat and builds up pressure pushing water into the overflow tank.
Thread
Thread Starter
Forum
Replies
Last Post
[For Sale] .045 thick Cometic Head Gaskets 4.060 bore
igotta355z28
LSX and LTX Parts
6
04-11-2016 08:21 AM