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Greg999
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Joined: August 19, 2016
Posts: 3
Location: Canada
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 Posted: Fri Aug 19, 2016 10:56 am Post subject: coolant boiling |
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| Ok first time posting here. I have searched this site but can't seem figure out what's up with my 84 Westy. Here's what's happening. A heater hose let go (rubbed on axle) so I replaced the hose, then refilled with coolant and bled as per instructions in Bentley manual. I thought I had it all good then a day later I took it for about a 20 minute drive, stopped then noticed coolant pouring out of the expansion tank. It cracked the tank right at the seam. The coolant was boiling in the reservoir. I let it cool down and then tried to bleed the air out as I figured that is why it was boiling. When I bled it I could not get bubble free coolant coming out at the rad bleed screw. Nothing would come out of the rear bleed screw but it could be stuck. I refilled the tank and tried it again hoping for the best but the same thing happened. By the way the temp gauge stayed only at 1/4, well below the led while I was driving the van even when the coolant was boiling. After another 5 minutes the temp gauge shot up and the led did start flashing. If someone could help me with this I would certainly appreciate it. Thanks. |
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bluebus86
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Joined: September 02, 2010
Posts: 11075
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| Posted: Fri Aug 19, 2016 11:03 am Post subject: Re: coolant boiling |
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a cracked open tank will cause loss of pressure, the pressure is required to prevent boiling. that may be the issue. look up "libby bong" for a neat and easy bleeding procedure.
on my van a leaky pressure cap caused boiling, got a new cap and then the plastic tank ruptured!ssthe van is tricky to bleed out air, that is why the libby bong was invented. give that ago, no longer need you have to raise the vans front and go thru the bentely proceedure.
also be sure you have correct coolant mix as too little will casue boiling to happen too soon.
good luck
_________________
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Vanagon Nut
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Joined: February 08, 2008
Posts: 10379
Location: Sunshine Coast B.C.
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| Posted: Fri Aug 19, 2016 11:12 am Post subject: Re: coolant boiling |
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Use an infrared temp "gun" to confirm if engine temps are ok.
At very least, it'll confirm if temp gauge
is "correct". Early style cooling system coolant low module
blinks red light and pins needle if coolant is low.
A cracked coolant expansion tank could be due to age and/or lack of build
quality. (e.g. some Meyle). Assuming the cooling system was working correctly
before the hose failure, I doubt what you're seeing is due to a compression leak
in engine.
Neil.
_________________
1981 Westy DIY 15º ABA
1988 West DIY 50º ABA
VE7TBN |
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Ahwahnee
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Joined: June 05, 2010
Posts: 9810
Location: Mt Lemmon, AZ
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| Posted: Fri Aug 19, 2016 11:59 am Post subject: Re: coolant boiling |
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| Vanagon Nut wrote: |
...Assuming the cooling system was working correctly
before the hose failure, I doubt what you're seeing is due to a compression leak in engine. |
Hopefully not -- but the IR thermometer mentioned will let you tell the difference between 'boiling' and 'combustion gas bubbles'. |
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Vanagon Nut
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Joined: February 08, 2008
Posts: 10379
Location: Sunshine Coast B.C.
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| Posted: Fri Aug 19, 2016 12:11 pm Post subject: Re: coolant boiling |
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| Ahwahnee wrote: |
| Vanagon Nut wrote: |
| .... I doubt what you're seeing is due to a compression leak in engine. |
Hopefully not -- but the IR thermometer mentioned will let you tell the difference between 'boiling' and 'combustion gas bubbles'. |
Indeed. And I hope I didn't alarm the OP.
Are there particular spots on the 1.9 that will show the highest temps
when checking with the IR thermometer?
_________________
1981 Westy DIY 15º ABA
1988 West DIY 50º ABA
VE7TBN |
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jimf909 
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Joined: April 03, 2014
Posts: 7476
Location: WA/ID
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| Posted: Fri Aug 19, 2016 2:51 pm Post subject: Re: coolant boiling |
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| Vanagon Nut wrote: |
Use an infrared temp "gun" to confirm if engine temps are ok.
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Where should the gun be pointed and what temps are okay?
_________________
- Jim
| Abscate wrote: |
Do not get killed, do not kill others.
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Current: 1990 Westy Camper - Bostig RG4, 2wd, manual trans w/Peloquin, NAHT high-top, 280 ah LFP battery, 160 watts solar, Flash Silver, seam rust, bondo, etc., etc.
Past: 1985 Westy Camper - 1.9 wbx, 2wd, manual trans, Merian Brown, (sold after 17 years to Northwesty who converted it to a Syncro). |
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bluebus86
Banned
Joined: September 02, 2010
Posts: 11075
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| Posted: Fri Aug 19, 2016 3:28 pm Post subject: Re: coolant boiling |
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no sense using a temperature gun until you have the system properly filled and purged of air, that should be done before taking temp measurements as failure to have the system properly filled and purged of air can cause temp problems.
the boiling could well be a symptom of the leaky coolant pressure tank.
so get the system filled and purged, check for leaks thus assuting you can maintain pressure, and then see if it still over heats or not, if it still over heats then proceed with additional diagnostics.
good luck
_________________
Help Prevent VW Engine Fires, see this link.....Engine safety wire information
Stop introducing dirt into your oil when adjusting valves ... https://www.thesamba.com/vw/forum/viewtopic.php?t=683022 |
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atomatom
Samba Member
Joined: May 15, 2012
Posts: 1867
Location: in an 84 Westy or Bowen Island, BC
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| Posted: Fri Aug 19, 2016 3:44 pm Post subject: Re: coolant boiling |
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yes, ensure the system is full of coolant, no point in checking steam or cooking it.
you can check the temp by pointing it at the waterpump - there are a few wires coming out, the temp-ii and dash temp sensors are there.
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84 Vanagon Westy, 1.9L, California raised but defected to Canada. |
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Ahwahnee
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Joined: June 05, 2010
Posts: 9810
Location: Mt Lemmon, AZ
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| Posted: Fri Aug 19, 2016 3:46 pm Post subject: Re: coolant boiling |
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Yes, by all means start by assuring the system is full and bled.
As for the IR gun -- there are several places it may prove useful.
You can confirm the accuracy of the sender & gauge by pointing it close to the sender for the gauge. That is the single wire sensor (possibly black) on or near the thermostat housing.
You can use it to assess the effectiveness of the radiator by pointing it at various spots to get an idea of temperature drop top to bottom and to look for any cooler areas that might suggest blockage.
You can use it to verify your electric rad fan is coming on at the right temp.
You can use it to confirm when the thermostat opens.
And, if the 'boiling' recurs you can point it at that tank and see if the bubbles are because the temp is about 212° or if something else in going on.
As for 'what temps are okay?' that will depend on many factors including the thermostat that is in there (you probably do not know), the ambient temperature, condition of the engine and the state of tune -- but broadly speaking an operating temp of say 180° to 190° is more or less fine.
Bear in mind there is a world of difference between 'runs hot' and 'overheats' so when you get to the point of taking temperatures you are learning what is normal for your engine. Obviously if you encounter a run-away out-of-control heat problem you shut it down and diagnose. |
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bluebus86
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Joined: September 02, 2010
Posts: 11075
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| Posted: Fri Aug 19, 2016 4:02 pm Post subject: Re: coolant boiling |
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| Ahwahnee wrote: |
Yes, by all means start by assuring the system is full and bled.
As for the IR gun -- there are several places it may prove useful.
You can confirm the accuracy of the sender & gauge by pointing it close to the sender for the gauge. That is the single wire sensor (possibly black) on or near the thermostat housing.
You can use it to assess the effectiveness of the radiator by pointing it at various spots to get an idea of temperature drop top to bottom and to look for any cooler areas that might suggest blockage.
You can use it to verify your electric rad fan is coming on at the right temp.
You can use it to confirm when the thermostat opens.
And, if the 'boiling' recurs you can point it at that tank and see if the bubbles are because the temp is about 212° or if something else in going on.
As for 'what temps are okay?' that will depend on many factors including the thermostat that is in there (you probably do not know), the ambient temperature, condition of the engine and the state of tune -- but broadly speaking an operating temp of say 180° to 190° is more or less fine.
Bear in mind there is a world of difference between 'runs hot' and 'overheats' so when you get to the point of taking temperatures you are learning what is normal for your engine. Obviously if you encounter a run-away out-of-control heat problem you shut it down and diagnose. |
of course if it is boiling it will boil at 212F at one atmosphere if it is pure water, However the addition of antifreeze and pressurization will increase the boiling point considerably. hence the need to have a sealed pressurized system with proper amount of antifreeze.
_________________
Help Prevent VW Engine Fires, see this link.....Engine safety wire information
Stop introducing dirt into your oil when adjusting valves ... https://www.thesamba.com/vw/forum/viewtopic.php?t=683022 |
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Terry Kay
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Joined: June 22, 2003
Posts: 13331
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| Posted: Fri Aug 19, 2016 4:06 pm Post subject: Re: coolant boiling |
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Perhaps the coolant is boiling because he's got a hole in that expansion tank, and no pressure in the system.
That would do it pretty quick as soon as it got hot.
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T.K.
Last edited by Terry Kay on Sat Aug 20, 2016 7:37 am; edited 1 time in total |
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atomatom
Samba Member
Joined: May 15, 2012
Posts: 1867
Location: in an 84 Westy or Bowen Island, BC
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| Posted: Fri Aug 19, 2016 4:09 pm Post subject: Re: coolant boiling |
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unless the thermostat is malfunctioning, the van will idle at 87oC when warmed up. even driving it around and it shouldn't exceed 100oC unless it is a hot day or driving fast/up hills.
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84 Vanagon Westy, 1.9L, California raised but defected to Canada. |
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bluebus86
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Joined: September 02, 2010
Posts: 11075
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| Posted: Fri Aug 19, 2016 4:16 pm Post subject: Re: coolant boiling |
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| Greg999 wrote: |
| Ok first time posting here. I have searched this site but can't seem figure out what's up with my 84 Westy. Here's what's happening. A heater hose let go (rubbed on axle) so I replaced the hose, then refilled with coolant and bled as per instructions in Bentley manual. I thought I had it all good then a day later I took it for about a 20 minute drive, stopped then noticed coolant pouring out of the expansion tank. It cracked the tank right at the seam. The coolant was boiling in the reservoir. I let it cool down and then tried to bleed the air out as I figured that is why it was boiling. When I bled it I could not get bubble free coolant coming out at the rad bleed screw. Nothing would come out of the rear bleed screw but it could be stuck. I refilled the tank and tried it again hoping for the best but the same thing happened. By the way the temp gauge stayed only at 1/4, well below the led while I was driving the van even when the coolant was boiling. After another 5 minutes the temp gauge shot up and the led did start flashing. If someone could help me with this I would certainly appreciate it. Thanks. |
also pressure test the cap on the presure tank, if it leaks you can get boiling as the system wont be pressurized.
remember you need a pressurized system and proper coolant mix, and the system properly led. if you have that and she boils over still, then look for other problems bad motor, blocked radiator, etc....
it appears you are still having problems beleeding the sysyste (stuck bleeder screw) so address that, make sure the cap is holding pressure,also.
_________________
Help Prevent VW Engine Fires, see this link.....Engine safety wire information
Stop introducing dirt into your oil when adjusting valves ... https://www.thesamba.com/vw/forum/viewtopic.php?t=683022 |
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Ahwahnee
Samba Member
Joined: June 05, 2010
Posts: 9810
Location: Mt Lemmon, AZ
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| Posted: Fri Aug 19, 2016 4:31 pm Post subject: Re: coolant boiling |
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| Greg999 wrote: |
| ...When I bled it I could not get bubble free coolant coming out at the rad bleed screw. Nothing would come out of the rear bleed screw but it could be stuck... |
If the 'rear bleed screw' you are referring to is the one on the big (black plastic or billet aluminum) fixture that the big hoses connect to -- nothing should come out. It just opens a passage via that small hose. I have sometimes forgotten to open it at all and still got the system bled just fine.
Be sure you have the valves for all the heaters (front and rear) full on to do the bleed. |
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Greg999
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Joined: August 19, 2016
Posts: 3
Location: Canada
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| Posted: Sat Aug 27, 2016 6:26 pm Post subject: Re: coolant boiling |
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| Ok thanks for the help. I have been away on a backpacking trip so haven't been able to work on the van. Now I have some time. So a few things I am still curious about.......what do I do if I can't get bubble free coolant to come out of the bleed screw at the rad? Should I completely remove that screw when I am bleeding the system? What about the temp gauge never coming above 1/4 until well after the coolant starts boiling and spewing all over everything? I think the overflow tank came apart as a result of the amount of pressure pushing on it after it started boiling. I don't think that was cracked before hand. While I am running the engine and trying to bleed the system I noticed bubbles coming from the hose and spilling into the expansion tank. Could that be a sign of a head gasket lead? |
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djkeev
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Joined: September 30, 2007
Posts: 32632
Location: Reading Pennsylvania
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Jeroen_M625
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Posts: 74
Location: Breda (NL)
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| Posted: Sun Aug 28, 2016 5:26 am Post subject: Re: coolant boiling |
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| Was your screw maybe replaced? Because that is how it should work original by VW, you do not have to remove the screw, just lossen it a few turns. |
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djkeev
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wesitarz
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Joined: August 20, 2012
Posts: 1491
Location: Victoria,B.C.Canada
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| Posted: Sun Aug 28, 2016 8:09 am Post subject: Re: coolant boiling |
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| djkeev wrote: |
New behr radiator but OEM screw hadn't a bleed slot either.....
New Radiator bleed screw ready for bleed slot.....
Dave |
Change your coolant regularly or not that bleed screw is prone to corrosion.Worth putting some anti-seize on it. |
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Ahwahnee
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Joined: June 05, 2010
Posts: 9810
Location: Mt Lemmon, AZ
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| Posted: Sun Aug 28, 2016 8:18 am Post subject: Re: coolant boiling |
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My (original) screw is already slotted (all the way up, not just nicked with a hacksaw). It also uses a nylon washer so it seals completely with only modest tightening.
Is it brass or steel? I do not recall offhand. |
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