BHG symptoms...but no BHG?

RNEMESiS42 · 08-26-2009, 04:52 AM

My birdcage light has been coming on and off every once and a while ever since I bought my car four years ago. Around last April I was driving my car when all of a sudden I saw steam coming up from the hood. I pull over and see that my radiator overflow tank is filling up. The temperature gauge in my car looked normal. I drove home and parked my car indefinitely, fearing a blown head gasket. I haven't driven my car since then and recently decided to test it for a BHG. I purchased the $45 block test kit form NAPA, and tried it out. I did it twice, and got negative results for exhaust gases in the coolant. Afterward I drove it about a half mile and back, and noticed when I parked that the same issue is occurring: coolant spilling out into the overflow tank.
What could be wrong? Thermostat or radiator busted? I have no other signs that would relate to a BHG.

btwilson86 · 08-26-2009, 07:20 AM

Have you ever messed with the line going in and the line going out of the cap on your overflow? If so, you might have them backwards....

Basically what would happen is this: as your car heats up, pressure forces coolant into overflow through the tube that feeds to the bottom of the reservoir. As the car cools down, it'll suck the coolant back into the cooling system via that same hose.

If the lines are backwards, as the coolant expands it'll fill up the reservoir as it normally should. The problem is, it can't drink it back up cuz the line running from the radiator is not hooked up to that little hose that goes to the bottom of the reservoir. So the coolant will just sit in there.

Next time you drive the car, more coolant will try to go into the reservoir. Once it's full it's gonna go straight out that other line on the overflow cap, which is the purge line that goes straight to the ground, thus making it seem like an over-pressurized cooling system (like with a blown head gasket) when in reality it's just 2 hoses hooked up backwards.

That was alot longer than I thought it'll be, sorry for the ramble

RNEMESiS42 · 08-26-2009, 07:30 AM

Thanks for the response, I'll check it out in the morning. I've never directly messed with my overflow tank, but it sure would be nice if it's as simple as this.

RNEMESiS42 · 08-26-2009, 05:56 PM

There's just the one line from the top of my radiator to the cap of the overflow. It all looks fine to me.

Bill UK · 08-26-2009, 08:12 PM

1. Thermostat not opening. (stuck closed)
2. Water pump impellor vanes corrode.
3. Blocked rad
4. Viscous fan coupling slipping
5. Also check this out Link

oregonjoe · 08-28-2009, 02:00 AM

I too had the same problems, blowing coolant out reservoir, no hot temp on gauge, negative test for exhaust gas – but in the end, it still was a BHG, The best test for BHG in No 6 cylinder is to look at spark plug – you will see a difference in the plug for the BHG cylinder compared to the rest (looks like the coolant color). The EG test does not find minor leaks when the compression is high.

Looks at the plugs and if it looks like a BHG, Runs like a BHG and smells like a BHG – then it probably is!

I had to pull and rebuild my engine as a result.

RNEMESiS42 · 08-28-2009, 06:40 PM

Damn, I'll look at the plugs, then. A few of those plugs are so annoying to get at, though!

RNEMESiS42 · 09-29-2009, 10:19 PM

SO, I thought the easiest and cheapest thing to do would be to replace the thermostat for starters. I picked one up form NAPA and proceeded to replace it. The bolts for the thermostat housing were rusted, and BOTH of them broke at the head when I was using a socket to get them out. This left the rest of the bolts stuck on the part that's attached to the engine.
Does anyone know the part number for this so I can replace it? All I can find is the thermostat housing (number 8 in the picture below), not the piece that it attaches to.

2jzmaestro · 09-29-2009, 11:09 PM

good thing you asked.

i bought parts for my 2jz at http://toyotapartszone.com

they have something called "hot spots" on their digram

gives you all the parts name and number

its a really helpful website and cheap parts

hope this helps

RNEMESiS42 · 09-29-2009, 11:11 PM

Phew...I just found the part number in this thread:

I'm going to to buy that sucker and the gasket, and be on my way...this has been l the fun replacement of a thermostat ever.

08-26-2009, 04:52 AM	#1
RNEMESiS42 Intake Join Date: Oct 2005 Location: Mpls, MN Posts: 40	BHG symptoms...but no BHG? My birdcage light has been coming on and off every once and a while ever since I bought my car four years ago. Around last April I was driving my car when all of a sudden I saw steam coming up from the hood. I pull over and see that my radiator overflow tank is filling up. The temperature gauge in my car looked normal. I drove home and parked my car indefinitely, fearing a blown head gasket. I haven't driven my car since then and recently decided to test it for a BHG. I purchased the $45 block test kit form NAPA, and tried it out. I did it twice, and got negative results for exhaust gases in the coolant. Afterward I drove it about a half mile and back, and noticed when I parked that the same issue is occurring: coolant spilling out into the overflow tank. What could be wrong? Thermostat or radiator busted? I have no other signs that would relate to a BHG. __________________ White 1987 N/A. Automatic. Targa top. TEMS

08-26-2009, 07:20 AM	#2
btwilson86 Super Moderator Join Date: May 2007 Location: Billings, Montana Posts: 1,034	Have you ever messed with the line going in and the line going out of the cap on your overflow? If so, you might have them backwards.... Basically what would happen is this: as your car heats up, pressure forces coolant into overflow through the tube that feeds to the bottom of the reservoir. As the car cools down, it'll suck the coolant back into the cooling system via that same hose. If the lines are backwards, as the coolant expands it'll fill up the reservoir as it normally should. The problem is, it can't drink it back up cuz the line running from the radiator is not hooked up to that little hose that goes to the bottom of the reservoir. So the coolant will just sit in there. Next time you drive the car, more coolant will try to go into the reservoir. Once it's full it's gonna go straight out that other line on the overflow cap, which is the purge line that goes straight to the ground, thus making it seem like an over-pressurized cooling system (like with a blown head gasket) when in reality it's just 2 hoses hooked up backwards. That was alot longer than I thought it'll be, sorry for the ramble __________________ 1989 7MGTE R154 Targa Top White Package w/Blue Interior Driftmotion 57trim CT26, Upgraded Intercooler, 2.25" Hard Pipes, 3" Turbo Back Exhaust with Test Pipe, HKS VPC w/GM 3 bar MAP sensor, APEXi S-AFC, Walbro 255lph fuel pump, ProSport EVO Series Boost / Fuel Pressure / AFR gauges, Lotek a Pillar Gauge Pod, HKS Type 0 Turbo Timer, Eibach Lowering Springs, Tokico Illumina II TEMS struts, custom powder coated Motegi Racing TrakLite wheels

08-26-2009, 07:30 AM	#3
RNEMESiS42 Intake Join Date: Oct 2005 Location: Mpls, MN Posts: 40	Thanks for the response, I'll check it out in the morning. I've never directly messed with my overflow tank, but it sure would be nice if it's as simple as this. __________________ White 1987 N/A. Automatic. Targa top. TEMS

08-26-2009, 05:56 PM	#4
RNEMESiS42 Intake Join Date: Oct 2005 Location: Mpls, MN Posts: 40	There's just the one line from the top of my radiator to the cap of the overflow. It all looks fine to me. __________________ White 1987 N/A. Automatic. Targa top. TEMS

08-28-2009, 02:00 AM	#6
oregonjoe 3" Exhaust Join Date: Aug 2009 Location: Southern Oregon Coast Posts: 83	If it smells like a BHG I too had the same problems, blowing coolant out reservoir, no hot temp on gauge, negative test for exhaust gas – but in the end, it still was a BHG, The best test for BHG in No 6 cylinder is to look at spark plug – you will see a difference in the plug for the BHG cylinder compared to the rest (looks like the coolant color). The EG test does not find minor leaks when the compression is high. Looks at the plugs and if it looks like a BHG, Runs like a BHG and smells like a BHG – then it probably is! I had to pull and rebuild my engine as a result.

08-26-2009, 08:12 PM	#5
Bill UK AEM EMS Join Date: Jul 2006 Location: UK Posts: 891	1. Thermostat not opening. (stuck closed) 2. Water pump impellor vanes corrode. 3. Blocked rad 4. Viscous fan coupling slipping 5. Also check this out Link

08-28-2009, 06:40 PM	#7
RNEMESiS42 Intake Join Date: Oct 2005 Location: Mpls, MN Posts: 40	Damn, I'll look at the plugs, then. A few of those plugs are so annoying to get at, though! __________________ White 1987 N/A. Automatic. Targa top. TEMS

09-29-2009, 10:19 PM	#8
RNEMESiS42 Intake Join Date: Oct 2005 Location: Mpls, MN Posts: 40	SO, I thought the easiest and cheapest thing to do would be to replace the thermostat for starters. I picked one up form NAPA and proceeded to replace it. The bolts for the thermostat housing were rusted, and BOTH of them broke at the head when I was using a socket to get them out. This left the rest of the bolts stuck on the part that's attached to the engine. Does anyone know the part number for this so I can replace it? All I can find is the thermostat housing (number 8 in the picture below), not the piece that it attaches to. __________________ White 1987 N/A. Automatic. Targa top. TEMS

09-29-2009, 11:09 PM	#9
2jzmaestro Stock Join Date: Sep 2009 Location: LOS ANGELES Posts: 25	good thing you asked. i bought parts for my 2jz at http://toyotapartszone.com they have something called "hot spots" on their digram gives you all the parts name and number its a really helpful website and cheap parts hope this helps

09-29-2009, 11:11 PM	#10
RNEMESiS42 Intake Join Date: Oct 2005 Location: Mpls, MN Posts: 40	Phew...I just found the part number in this thread: I'm going to to buy that sucker and the gasket, and be on my way...this has been l the fun replacement of a thermostat ever. __________________ White 1987 N/A. Automatic. Targa top. TEMS

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Blown Head Gasket Symptoms!	Dejvid1785	MKIII FAQ	76	04-24-2011 07:59 PM
86.5 and 87 symptoms	sd88supra	MKIII Supra	8	12-05-2007 08:56 AM
88 turbo, Any idea on what causes these symptoms?	christutecky	MKIII Supra	0	02-02-2007 07:19 PM
Strange syptoms	rob Johnson	MKII Supra	9	10-28-2005 03:16 PM
NEW OWNER! (whatre the symptoms of a...)	91SupraTURBO	MKIII Supra	11	07-13-2005 12:03 PM