Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×


Reply
 
Thread Tools Display Modes
 
Old 10-25-2019, 09:27 PM   #21
Bus Geek
 
Join Date: Sep 2018
Posts: 2,831
Year: 2007
Coachwork: Thomas Built
Chassis: Minotour
Engine: Chevy Express 3500 6.6l
Quote:
Originally Posted by OlgaAK View Post
What if it is three minutes? It looks like I can get a kit to test for combustion gases in the radiator at the same kind of shop that will have a thermostat. But I am anxious now and will appreciate any info.
If it’s 3 minutes coolant is not circulating. It’s sitting in the water jacket until it boils. Normally in that time the thermostat would open and the water pump would move coolant.

Why was your radiator replaced?

Danjo is offline   Reply With Quote
Old 10-25-2019, 09:44 PM   #22
Bus Nut
 
Join Date: Mar 2011
Location: Port angeles, Wa
Posts: 318
Year: 90
Coachwork: bluebird conventional
Chassis: international
Engine: dt466
Rated Cap: 72
Quote:
Originally Posted by bluebird90 View Post
If the bubbles start within seconds of starting, I think you have a combustion leak when cold. Go to the parts store and get a block testing kit. That will tell if you have a blown head gasket or not.
I misread your timeline. Even after several minutes it could still be a head gasket. The block test would tell. I have also seen water pumps with corroded or broken impellers create this. Do the block test
bluebird90 is offline   Reply With Quote
Old 10-25-2019, 10:22 PM   #23
Bus Geek
 
EastCoastCB's Avatar
 
Join Date: Sep 2014
Location: Eustis FLORIDA
Posts: 23,764
Year: 1999
Coachwork: Thomas
Chassis: Freighliner FS65
Engine: Cat 3126
Rated Cap: 15
Quote:
Originally Posted by Johnny Mullet View Post
If the bubbles are showing up and building high pressure before it even warms up then I suspect compression is getting into the cooling system from a head gasket or cracked head/block.
Yeah a bad head gasket can/will do that.

First things I'd check would be the cap, thermostat, and I'd make sure all the air was bled out of the system.
EastCoastCB is offline   Reply With Quote
Old 10-25-2019, 10:27 PM   #24
Bus Geek
 
EastCoastCB's Avatar
 
Join Date: Sep 2014
Location: Eustis FLORIDA
Posts: 23,764
Year: 1999
Coachwork: Thomas
Chassis: Freighliner FS65
Engine: Cat 3126
Rated Cap: 15
Quote:
Originally Posted by OlgaAK View Post
What is a compression test? I will need to run it to get to the store and back. About 60 minutes total driving.
an hour with a cooling system failure and your engine could be nuked. It may not even live the whole hour. Its nothing to mess around with.
EastCoastCB is offline   Reply With Quote
Old 10-26-2019, 01:41 AM   #25
Bus Crazy
 
bus-bro's Avatar
 
Join Date: May 2007
Location: Whidbey Island, WA.
Posts: 1,109
Year: 1984
Coachwork: Blue Bird
Chassis: All American
Engine: 3208 na boat anchor
Rated Cap: 2
Off hand, it looks to be compression/combustion gas leaking into the jacket (coolant) water, so I'd say a coolant test is where I'd start. When you're looking at it on idle it might seal up when the engines warms up, but under load it will blow.

This is my experience in the marine world: I ran some engines with some serious liner cracks for a few hours, but turn the engine off and the coolant disappears.
bus-bro is offline   Reply With Quote
Old 10-26-2019, 10:57 AM   #26
Skoolie
 
Join Date: Apr 2019
Location: A bus
Posts: 104
Year: 2003
Coachwork: Thomas
Engine: Cummins 5.9 + Allison 3060
Rated Cap: Full size
To clarify, when I say that the expansion tank is boiling, I mean there are a lot of bubbles. The fluid is not actually very hot.

I am not in a place until later today to drain the radiator level to be able to directly test the gases in the radiator itself, but I used the block testing kit on the expansion tank and it is staying blue.

How much faith can be put in a test done using the expansion tank rather than the radiator itself?

I drove the bus 20 min this morning and it wasn't until I got to the shop that the engine temp dial finally hit 180. It stayed at 100 for the first half of the drive, despite that being somewhat mountainous roads.

I bought a new thermostat and some form-a-gasket, plus pfte tape to reseal the bolt on the bottom of the radiator. I'm also going to get some Blue Devil and read up on water pumps and maybe buy some parts for that before going to a place where I can really work on this.
Attached Thumbnails
1453188E-C710-481B-A12B-E34E1DFA0CE9.jpg  
OlgaAK is offline   Reply With Quote
Old 10-26-2019, 11:00 AM   #27
Skoolie
 
Join Date: Apr 2019
Location: A bus
Posts: 104
Year: 2003
Coachwork: Thomas
Engine: Cummins 5.9 + Allison 3060
Rated Cap: Full size
Quote:
Originally Posted by Danjo View Post
Why was your radiator replaced?
Because my (now-former) mechanic told me that the leak I was seeing was due to a faulty radiator. Since then it has become clear that the fluid is coming from the pinhole in the expansion tube. I think he just wanted to sell me an expensive repair and took advantage of my trust.
OlgaAK is offline   Reply With Quote
Old 10-26-2019, 11:30 AM   #28
Bus Crazy
 
Join Date: May 2018
Location: topeka kansas
Posts: 1,771
Year: 1954
Coachwork: wayne
Chassis: old f500- new 2005 f-450
Engine: cummins 12 valve
Rated Cap: 20? five rows of 4?
that line marked in red

in your first post... think of it as a way for steam or air to get out of the cooling system... when that starts having bubbles or boiling go through the the smaller hose.. is the smaller hose hot to the touch? when the small hose is hot to the touch does the bigger, upper hose get hot also? If the smaller hose is like too hot to touch and the bigger hose is cool enough to hang onto or cold, that would indicate the thermostat is not opening very far or not opening at all. the cool water from the radiator is sucked up from the lower hose pump through the engine block, up through the cylinder head then out through the thermostat and upper radiator hose. when the thermostat is shut there is usually a small "bypass" hose to allow a minimal about of coolant to circulate, this also helps in the case of a stuck thermostat.


william
magnakansas is offline   Reply With Quote
Old 10-26-2019, 11:35 AM   #29
Bus Crazy
 
Join Date: May 2018
Location: topeka kansas
Posts: 1,771
Year: 1954
Coachwork: wayne
Chassis: old f500- new 2005 f-450
Engine: cummins 12 valve
Rated Cap: 20? five rows of 4?
do you have time to telephone?

discuss test strategy and trouble shooting.

seven eight five too zero seven seventysixhundred

william
magnakansas is offline   Reply With Quote
Old 10-26-2019, 01:21 PM   #30
Skoolie
 
Join Date: Apr 2019
Location: A bus
Posts: 104
Year: 2003
Coachwork: Thomas
Engine: Cummins 5.9 + Allison 3060
Rated Cap: Full size
God bless the guy who was working at the auto parts store. He used to work for Cummins and spent over two hours in my bus pointing out all the most likely issues. He said that he didn't like my 9 pound radiator cap and sold me a 13 pound one. I got the bus up to about 200 degrees just now and peeked in the expansion tank and don't see any bubbles. Maybe this issue was just the radiator cap? I will keep looking in that tank and listening for sounds. On the other hand, there is something defective with the radiator fan and I will begin researching how to fix that. It's not related to the bubbling though and isn't an urgent issue. It just explains why the bus runs slightly hotter when I'm stuck in traffic than while on the highway.
OlgaAK is offline   Reply With Quote
Old 10-26-2019, 07:31 PM   #31
Bus Geek
 
Join Date: Sep 2018
Posts: 2,831
Year: 2007
Coachwork: Thomas Built
Chassis: Minotour
Engine: Chevy Express 3500 6.6l
Wow that would be great if it’s just a radiator cap.
Danjo is offline   Reply With Quote
Old 10-26-2019, 08:59 PM   #32
Bus Geek
 
o1marc's Avatar
 
Join Date: Dec 2017
Location: Dawsonville, Ga.
Posts: 10,482
Year: 1999
Coachwork: Genesis
Chassis: International
Engine: DT466/3060
Rated Cap: 77
I fail to see where a loose fitting or not enough pressure cap is going to cause aeration of the water. I doubt the cap is the fix, though I also recommend a high PSI cap.
o1marc is offline   Reply With Quote
Old 10-27-2019, 03:11 AM   #33
Bus Nut
 
Truthseeker4449's Avatar
 
Join Date: Sep 2019
Location: Northern Virginia
Posts: 578
Year: 2001
Coachwork: Thomas
Chassis: MVP ER
Engine: CAT 3126
Quote:
Originally Posted by o1marc View Post
I fail to see where a loose fitting or not enough pressure cap is going to cause aeration of the water. I doubt the cap is the fix, though I also recommend a high PSI cap.
I have a theory based on some chemistry. When you increase pressure in a closed system like a cooling system, your boiling point will rise. IIRC, the boiling point of most coolants is not that much higher than regular water. In an engine that's running hot, it could be boiling the coolant out of the system. Apparently it's a significant issue in Ford versions of the 6.0l, and it seems most Fords in general as I'm always having to top them off.

Since OlgaAK mentioned that he thinks his fan is defective, thus lowering the cooling capacity at low speeds, it seems quite possible that could be why it was boiling coolant with a lower pressure cap but now is ok.
Truthseeker4449 is offline   Reply With Quote
Old 10-29-2019, 02:32 PM   #34
Skoolie
 
Join Date: Apr 2019
Location: A bus
Posts: 104
Year: 2003
Coachwork: Thomas
Engine: Cummins 5.9 + Allison 3060
Rated Cap: Full size
The problem came back. I called a dozen mechanics, all insisting that it must be a head gasket despite no other signs of that, before someone finally asked if it had air brakes and told me to come in.

Half an hour later, the mechanic had drained the air tanks and done some tests with the air compressor. The pressure in the radiator continues to rise even when the bus is off, well past the limit for either radiator cap (he stopped testing as it approached 30 psi).

It seems like the air compressor is leaking pressure into the radiator and needs to be replaced. The new part arrives tomorrow, repair planned for Thursday. Fingers crossed that this will be the last $1500+ repair for a while...
OlgaAK is offline   Reply With Quote
Old 10-29-2019, 02:52 PM   #35
Bus Geek
 
Join Date: Sep 2018
Posts: 2,831
Year: 2007
Coachwork: Thomas Built
Chassis: Minotour
Engine: Chevy Express 3500 6.6l
Ouch. Sorry to hear that!
Danjo is offline   Reply With Quote
Old 10-29-2019, 02:54 PM   #36
Skoolie
 
Join Date: Aug 2019
Location: Central missouri
Posts: 128
Chassis: 2000 Int Amtran
Engine: DT466HT
Rated Cap: 84
Sure beats a head gskt repair of worse a head.
MacC is offline   Reply With Quote
Old 10-29-2019, 05:32 PM   #37
Bus Geek
 
o1marc's Avatar
 
Join Date: Dec 2017
Location: Dawsonville, Ga.
Posts: 10,482
Year: 1999
Coachwork: Genesis
Chassis: International
Engine: DT466/3060
Rated Cap: 77
Quote:
Originally Posted by Truthseeker4449 View Post
I have a theory based on some chemistry. When you increase pressure in a closed system like a cooling system, your boiling point will rise. IIRC, the boiling point of most coolants is not that much higher than regular water. In an engine that's running hot, it could be boiling the coolant out of the system. Apparently it's a significant issue in Ford versions of the 6.0l, and it seems most Fords in general as I'm always having to top them off.

Since OlgaAK mentioned that he thinks his fan is defective, thus lowering the cooling capacity at low speeds, it seems quite possible that could be why it was boiling coolant with a lower pressure cap but now is ok.
I read it more as aeration, than boiling. Water boiling point does go up under pressure by about 3* PSI. A 12lb radiator cap will raise the boiling point to around 242*. I've never seen a slow boil in an overheating radiator.
o1marc is offline   Reply With Quote
Old 10-29-2019, 05:34 PM   #38
Bus Geek
 
o1marc's Avatar
 
Join Date: Dec 2017
Location: Dawsonville, Ga.
Posts: 10,482
Year: 1999
Coachwork: Genesis
Chassis: International
Engine: DT466/3060
Rated Cap: 77
Can someone explain to me the relationship of air in the radiator from a brake compressor? The systems are not connected in any way. Sounds like you're about to be taken for $1500.
o1marc is offline   Reply With Quote
Old 10-29-2019, 06:29 PM   #39
Bus Crazy
 
Join Date: Feb 2019
Location: New Hampshire
Posts: 1,349
Year: 1990
Coachwork: Thomas 4 window w/lift
Chassis: G30~Chevy cutaway
Engine: 5.7/350 Chevy Vortec
Rated Cap: Just me and my "stuff"?
Quote:
Originally Posted by o1marc View Post
Can someone explain to me the relationship of air in the radiator from a brake compressor? The systems are not connected in any way. Sounds like you're about to be taken for $1500.
X2, Olga.
Don't know your bus engine wise but, hard to believe the compressor is cooled by the radiator or any other part of the engine coolant/system.
Try to get a 2nd opinion if not too late!
peteg59 is offline   Reply With Quote
Old 10-29-2019, 07:46 PM   #40
Bus Geek
 
o1marc's Avatar
 
Join Date: Dec 2017
Location: Dawsonville, Ga.
Posts: 10,482
Year: 1999
Coachwork: Genesis
Chassis: International
Engine: DT466/3060
Rated Cap: 77
Quote:
Originally Posted by peteg59 View Post
X2, Olga.
Don't know your bus engine wise but, hard to believe the compressor is cooled by the radiator or any other part of the engine coolant/system.
Try to get a 2nd opinion if not too late!
Nothing but oil going through the compressor. Oil is cooled by the radiator, but not directly. The first thing that comes to mind when I see bubbles in the radiator, and think of a blown head gasket, I look for milky oil.
o1marc is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Featured Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 08:20 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2024, vBulletin Solutions, Inc.