hi all,
did a search and can't seem to find what I need.
The engine in question is from a 83 sd (617)that i transplanted into my IHC Travelll a few years back. Whats happening is even after the truck is ice cold,the upper radiator hose is hard. The coolant overflow tank is empty utill I release cap which has alot of presure and then some coolant will fill back up into the reservoir. I have a new cap on it which is a 120. I could not find a 100. Also note that the reservoir might be mounted a little higher in the engine bay as compared to how it is in the sd and i also have a vegoil system in place so the coolant amount is alot because of the hoses going to the rear. The truck does not run hot and gives good heat. I do have to add coolant quite often but i believe that is a heater core leak. Anyone have any ideas why there is always so much pressure in the system? Thanks Mike

You're adding coolant because the engine is consuming it.

Either the head gasket has failed or the head is cracked.

Do an oil analysis and confirm the presence of high sodium, potassium and the indicator for Glycol.

Don't ignore the problem.........the bearings don't particularly care for glycol.

That symptom is usually from exhaust gasses getting into the cooling system via a bad head gasket or a crack in the head or cylinder wall. Loosing coolant is not a good thing. If the heater core is leaking, you should be able to smell it while the heater is running

Check for bubbles reaching the tank while the engine is running.

Get a proper cap before chasing other problems, as a cap that is rated higher will hold too much pressure also.

__________________
RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

99 W210 E300 Turbo Diesel, chipped, DPF/Converter Delete. Still needs EGR Delete, 232K

90 Dodge D250 5.9 Cummins/5 speed. 400K

Gone and still missed...1982 w123 300D, 1991 w124 300D

it does sound bad.
if you are loosing coolant, but you have pressure in the hose when the motor is cold, it is unlikely to be a heater core... that would release the pressure, and cause a sweet smell in the cabin.
gently release the pressure, then start the motor with the cap off. you will most likely see bubbles in the expansion tank. if so, start shopping for a head gasket, or a donor motor... whichever you feel more comfortable with.
and get some pics of that conversion on here, I wanna do that to my T'all!
John

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

I'm going to chime in on this because I'm having the same problem on my '84, plus it likes to run about 96 C, but with the heater on it takes about a half hour to get up that high. The radiator, water pump, and t-stat(4x) are all new and I've parked it on a 45 degree+ hill to get the air out of the system to make sure that wasn't it. I've been trying to reason against head/head gasket issues because it starts up so smooth even in the teens with no block heater and its such a strong runner. I'm going to be getting a 1980 SD in a week or two so I'll be able to take the car down and see what's going on, if you guys thing its something seriouse. I can't right now because its my daily driver. I have no problems what-so-ever with pulling the head since I just finished this job on my project engine, and if it is cracked, my local pick-n-pull has at least twenty 617's if not more so getting a replacement will be no problem.

__________________
Seth

1984 300D 225K
1985 300D Donor body
1985 300D Turbo 165K. Totaled. Donor Engine. It runs!!!
1980 300SD 311K My New Baby.
1979 BMW 633csi 62K+++? Dead odo

Let me interject again. Not enough caffiene yet. Check every thing mentioned. Brian is so correct with the bearing not caring for glycol or water.

And, if you do have a coolant leak in the heater core, pressure would drop. If it leaks coolant, it will also leak air.

Sorry for not paying attention.

__________________
RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

99 W210 E300 Turbo Diesel, chipped, DPF/Converter Delete. Still needs EGR Delete, 232K

90 Dodge D250 5.9 Cummins/5 speed. 400K

Gone and still missed...1982 w123 300D, 1991 w124 300D

I believe there are tests trips available to dip in the coolant which detect the residues of exhaust gases.
One more remote possibility is that someone accidently dropped a bottle of Viagra into the cooling system.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

There is no issue with 96C. if that's the only symptom.

If you also have pressure overnight and loss of coolant, it's also recommended that you spring for the $20. and get the oil analysis. Why conjecture?

Likely its the head gasket. I went through the same issues as you on my '84 300D. Ran like a top, good heat, starts perfectly, etc. Used very little coolant to speak of but the coolant was turning dark from soot and the system was pressurized all the time, hot, cold, etc. If you can do an engine swap then a head will be easy. Recommend Metric Motors for a re-manufactured head. Do a search on my posts and you will see what I had to do. Oil analysis indicated coolant in my oil. RT

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When all else fails, vote from the rooftops!
84' Mercedes Benz 300D Anthracite/black, 171K
03' Volkswagen Jetta TDI blue/black, 93K
93' Chevrolet C2500HD ExCab 6.5TD, Two-tone blue, 252K

I usually only get pressure overnight say maybe once a month, no where near each time I shut it off. Also it doesn't pressurize right away, only after normal warming but it does get really solid when its warmed up all the way. My apologies, allow me to be more complete in my description. A few months ago I had to replace my water pump due to a leaking seal and I decided to do a citric acid flush while I had the system open. Either by coincidence or because of the flush, my thermostat failed closed, causing the temp gauge to peg for about thirty seconds before I noticed it. After replacing the radiator and t-stat, it now runs at 96C as opposed to the 82 it did before, never past 85. Also, I have had an oil analysis done and it did come back with sodium levels high enough to suspect anti-freeze. Attached is a copy of my results. Thanks.

Attached Thumbnails

 

__________________
Seth

1984 300D 225K
1985 300D Donor body
1985 300D Turbo 165K. Totaled. Donor Engine. It runs!!!
1980 300SD 311K My New Baby.
1979 BMW 633csi 62K+++? Dead odo

The change of the thermostat could be responsible for the temperature change to 96C. Seems too coincindental to the change in temperature. Again, the 96C. may only be the gauge reading.

I cannot see the results clearly to determine if there is glycol present in the sample. It appears that several categories on the bottom row read zero. One of them might be "anitifreeze"????

The high sodium level with a very low potassium level is not conclusive. The SD recently ran a sodium level of 35 and it definitely has no head issues.

In very cold weather, I don't see any possibility of the system running warm even if the head gasket has failed. The capability of the radiator to reject the heat load with 32F. ambient temperatures is almost unlimited.

See if you can confirm the head temperature with an infrared temperature measuring device. My SD runs 7C. less than the gauge indicates.

I don't know how feasible it is, or how accessible, but there are testers that you put on the reservoir in place of the cap that test for exhaust gases being blown out of your cooling system.

I used one borrowed from a mechanic in the family to locate a cracked head on a couple of my previous gassers, and was told that there was now a fluid that could detect diesel exhaust gases as well.

The tester that I used was a cone shaped rubber cork attached to a hose with a little squeeze bulb pump. pumping the bulb would pull whatever gases were in your cooling system out, and blow them down through a bubbler tip submerged in the test liquid. The liquid would change color to indicate the exhaust gases, and the speed of the change spoke of how bad the leak was.
(in the case of the one I'm thinking of, it changed in record time, according to the mechanic I borrowed the tester from. :p )

__________________
-Josh
Testing the cheap Mercedes axiom, one bolt at a time...

Didn't you add PROPANE to your truck? I bet you were running too much propane, it preignited and blew out the headgasket.

hi all,
I want to thank all for who responded. Well some good news this morning. The hose wasnt hard. What I did was I replaced the radiaor cap with a 7 pound cap. There was a 120 on it. This morning the hose was soft and no pressure in the system.
As far as the heater core, there is a slight leak there. The entire heater box is located in the engine bay. Think mid 70's chevy with factory A/C. I do get a drip running down the firewall but maybe with the less pressure it wont leak as bad.
I have ordered a oil test kit from blackstone labs and am curious to see what it shows. I will post results when I get it.
Great call on the propane. I hadn't thought of that. I do use it but have it regulated to maybe 3 lbs. Occasionally i get a sound I think is injector nailing and when it does that, I shut off the propane.
In general this truck has been awesome. In sept. I drove from long island to springfield ohio for a show. I drove almost the entire way there on veg oil.Climbed the hills beautifully. still got at least 20mpg.
The funny part is I drive this truck everyday and my 2002 ford F-350 dually sits in the driveway. A 1973 wins over a 2002. I am such a redneck! lol
Thanks again guys

Ok. I'm currently bidding on an ir temp gun on ebay so I can verify head temps. I've been wanting to get one for a while so now I'm going to break down and get one. Sorry I'm at school now and can't repost the oil analysis but it did say that lead was way high, indicating that something was attacking the bearings. That with the high sodium levels lead them to conclude I was getting antifreeze in my oil. That analysis was on the change before last and I'm due for another within the month and I'm going to have it analyzed as well. Thanks.

__________________
Seth

1984 300D 225K
1985 300D Donor body
1985 300D Turbo 165K. Totaled. Donor Engine. It runs!!!
1980 300SD 311K My New Baby.
1979 BMW 633csi 62K+++? Dead odo