chazglenn3

Coolant Purge Line

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Last week the upper radiator hose on my car was cut by the water pump tensioner pulley (due to improper routing). So, I replaced the hose and added coolant and three tabs. Last night while driving home, I noticed the motor was overheating. It was fine while driving, but would heat up while sitting at red lights. Today, I was checking around under the hood and the fans are working, the thermostat seems to be operating fine, and the surge tank was full, the only thing that didn't seem to be okay was when I pulled the purge line off of the surge tank, there was no flow. I removed the line and pushed a long cable tie as far in as I could to try and clear any blockage. I then put the hose back on the engine side and started the car...still no flow ( I let it run until the needle was in the center of the range and the upper hose was warm.) Any ideas on how I can clear this?

Charles


Charles

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Last week the upper radiator hose on my car was cut by the water pump tensioner pulley (due to improper routing). So, I replaced the hose and added coolant and three tabs. Last night while driving home, I noticed the motor was overheating. It was fine while driving, but would heat up while sitting at red lights. Today, I was checking around under the hood and the fans are working, the thermostat seems to be operating fine, and the surge tank was full, the only thing that didn't seem to be okay was when I pulled the purge line off of the surge tank, there was no flow. I removed the line and pushed a long cable tie as far in as I could to try and clear any blockage. I then put the hose back on the engine side and started the car...still no flow ( I let it run until the needle was in the center of the range and the upper hose was warm.) Any ideas on how I can clear this?

Charles

Check where the hose attaches to the engine, sometimes the opening is closed off. Try a metal coat hanger if the ties are too short. Have you checked the belt tensioner pulley on the waterpump side for binding or some slack?

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Cheap method would be to simply replace the surge tank line. Is this the line that connects to the "hollow bolt" in the water crossover?

Also, how "hot" is the engine getting, when sitting at stoplights?


Jason(2001 STS, White Diamond)

"When you turn your car on...does it return the favor?"

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With the engine stopped and cool, disconnect the purge line from the waterpump housing and remove the connector and clean it out. You can also blow compressed air through the purge line and see if it bubbles in the surge tank. That would assure the line is clear.


Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Jason;

I removed the line from the car and made sure there was no blockage in the line itself. The obstruction is somewhere on the engine side. Is this "hollow bolt" what the purge line connects to on the engine? It just looked like a metal fitting sticking up to me. At one point the car got hot enough for the "Engine Hot - AC Off" message to appear. But only once on the way home. At other lights, the needle just moved to about 3/4.

Kevin;

When you say to "remove the connector", are you referring to this metal fitting that the purge line was connected to?

Thanks, guys!

Charles


Charles

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Charles,

Yes on both counts. Remove the line and clear the fitting that it connects to or as Kevin said, blow it out with compressed air. The air will be purged once you start it again and rev to 3000 - 4000 RPM a few times.

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Okay, now I'm really confused. The line that I am thinking is the purge line is connected to the throttle body, and the FSM calls it the surge tank inlet hose. I assume I am looking at the wrong line. Is this inlet line the same as the purge line? And if it is, why is it connected to the throttle body instead of the water pump housing?

Charles


Charles

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The line that may be restricted is the line from the water pump housing to the surge tank. The connector is a hollow bolt/fitting.


Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Kevin;

Is this located near the larger surge tank hose? Down low? I'm heading back out to the garage to look again...

Charles

Okay, I see a bolt on a bracket with a hose connected to it. This hose however, is connected to the other throttle body fitting. The surge tank has only two hoses attached to it...the smaller upper hose and the largedr lower hose...


Charles

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No, it is attached to the side of the surge tank, near the top (above the coolant level). It is the small 3/8" upper line.

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It is a small hose that connects to the surge tank - upper driver's front side. It connects to a metal tube that goes under the beauty cover. It may connect the the TB - keep following it until it comes to the waterpump housing. Disconnect the hose at the waterpump housig and clean the hollow bolt.


Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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That's what I thought, Larry. But like I mentioned above, that hose is attached to one of the throttle body coolant lines, and I can't find the "hollow bolt", or what should be attached to the throttle body fitting if not the upper surge tank hose. I think I will try to get a picture and post it.


Charles

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Sadly, I don't have a source of compressed air. They must have changed the design when they added the water-cooled alternator in '98. The metal pipe that runs under the beauty cover goes to the alternator. Here are a couple of pics of the set up on my car.

[attachmentid=2959]

Another pic...

[attachmentid=2960]

Third pic...this is what appears to be the "hollow bolt" to me...the hose here is connected to the throttle body, and the other throttle body hose is connected to the surge tank line...maybe it loops through the throttle body before heading off to the surge tank. I'll pull the hose there and see what I find...

[attachmentid=2961]

post-1526-1166151404.jpg

post-1526-1166151494.jpg

post-1526-1166151543.jpg


Charles

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Yeah, that line in the second pic is it. If you don't have a compressor, just give it a blow job. It is probably just clogged with cooling system suppliment mush. Shouldn't take much to clear it.

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Okay...I removed the lower throttle body hose from the hollow bolt and to my surprise (not) there was no coolant coming from the small hole in the end of the bolt. I removed the bolt, and coolant came pouring out. I found an inch and a half long thin piece of rubber in the other end of the hollow bolt. Good thing it is late fall, as the throttle body was getting no coolant flow either. I put it back together and will take a test drive in a few. Now my concern is where did the piece of rubber come from...maybe a piece of gasket material?

Charles


Charles

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Yikes! Wonder how long it has been there. Glad you did not use the compressed air method. Hopefully it is the only piece, but if not and it happens again, you'll know here to look. I'm sure she will run just fine now.

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I cleared the air purge line in a matter of seconds with a Mityvac pump. Just connect tubbing from the Vac to the purge line at the surge tank end and vacuum it out. the Mityvac will have no problem creating enough suction to clear the line.

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Test drive was successful! Thanks to all that replied to help me solve my problem. I will read and post on the other forum, but when I need help with an issue, this is where I come :)

Charles


Charles

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That little piece of rubber still bothers me. I'd consider changing all of the hoses in the cooling system if I were you, as well as changing the coolant. I know it's against all recomendations to FLUSH a cooling system, but this would be the one instance that I would do it. I'm not talking "flush machine" type flush, but a "garden hose" type flush. If this engine was ever on a flush machine, that MIGHT explain the little chunk of rubber. This sounds like the failure mode for older rubber hoses subjected to heat, I'd at least inspect the inside of the radiator hoses for drying and cracking. Notice that I said INSIDE, the outside might look fine, but still be cracked inside, where the hot coolant touches.


Never underestimate the amount of a persons greed.

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That bottom picture is the hollow bolt; it also bolts the engine lift bracket to the engine.

The water flow is from the pump, through that hollow bolt, through the throttle body, and then to the top part of the pressure tank.

If air pressure not available, you should be able to snake an old speedometer cable or a chocke cable through there. Or adapt a garden hose down to 3/8" somehow.


Jim

Drive your car.

Use your cell phone.

CHOOSE ONE !

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Hi All,

I had that same problem with the hollow bolt. I have extensive post on this site about that. My car was overheating also. i changed everything pertaining to my cooling system, and still no luck, until i got help from the guys on this site. I had rubber enlarged in the bolt also. I changed all of the hoses, i also purchased another one from the dearler, i enlarged the hole through out the bolt, and have not had a problem again. i'm glad you found the problem before you started replacing parts. ;)

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You said the waterpump pulley or what not ripped up a hose, could have been sucked threw the system from that ordeal, then tried to purge and got stuck.


The Green's Machines

1998 Deville - high mileage, keeps on going, custom cat-back exhaust

2003 Seville - stock low mileage goodness!

2004 Grand Prix GTP CompG - Smaller supercharger pulley, Ported Exhaust Manifolds, Dyno tune, etc

1998 Firebird Formula - 408 LQ9 Stroker motor swap and all sorts of go fast stuff

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