Re: [MBZ] overheating engines
Zoltan Finks wrote: > Okay, good to get into this talk about coolant and head gaskets. > > Let me ask this: One thing I noticed the day I bought the car is that > just a few moments after parking the car, the top radiator hose was > not hard. If the coolant is heated and the cooling system is sealed, then there will be more pressure in the system when the coolant is hot than when it is cold. 201 and 124 coolant reservoirs are notorious for cracking so there will be NO pressure whether hot or cold. New reservoirs are not terribly expensive (but more so than they used to be). If the cap has failed there may also be little or no pressure. Different Mercedes models built during the 1980s had 1.0, 1.2 and 1.4 bar pressure caps. Starting in the '90s Mercedes now supplies only 1.4 bar caps for all models and all years. The rubber parts of caps routinely fail in the 15-20 year time frame even in well maintained cars. > > And when you squeeze it (still does the same thing today) you hear > some sort of ticking noises from down in the engine somewhere. Could be the chatter of the thermostat vents. No idea what that means in your engine (by the way what year, engine and chassis are you describing - such information really is the only courteous way to engage in an extended discussion). Coolant being pushed thru the cooling passages usually makes a gurgling sound. > Do these conditions ring a bell with anyone? I'm used to a top > radiator hose being hard after shutting the engine off, as there's > pressure in the system. > > Why don't we start three posts: one for the impatient (*sigh*), and > one for those looking to make a snappy joke, and one for those who are > open to thoughtful questions. I have NO idea what that last sentence means. Was it a question? Isn't it still obligatory to use a question mark to end a question? Marshall -- Marshall Booth Ph.D. Ass't Prof. (ret.) Univ of Pittsburgh School of Medicine [EMAIL PROTECTED] ___ http://www.okiebenz.com For new parts see official list sponsor: http://www.buymbparts.com/ For used parts email [EMAIL PROTECTED] To Unsubscribe or change delivery options go to: http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] overheating engines
Replace the radiator cap. Peter ___ http://www.okiebenz.com For new parts see official list sponsor: http://www.buymbparts.com/ For used parts email [EMAIL PROTECTED] To Unsubscribe or change delivery options go to: http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] overheating engines
Okay, good to get into this talk about coolant and head gaskets. Let me ask this: One thing I noticed the day I bought the car is that just a few moments after parking the car, the top radiator hose was not hard. And when you squeeze it (still does the same thing today) you hear some sort of ticking noises from down in the engine somewhere. Do these conditions ring a bell with anyone? I'm used to a top radiator hose being hard after shutting the engine off, as there's pressure in the system. Why don't we start three posts: one for the impatient (*sigh*), and one for those looking to make a snappy joke, and one for those who are open to thoughtful questions. Brian On 9/26/07, Peter Frederick <[EMAIL PROTECTED]> wrote: > Glycol raises the boiling point of the coolant to around 240F, pressure > cap raises the BP to around 260F. However, if the coolant is not > circulating, the head can get really hot, and both differential > expansion of the parts of the head and the difference in expansion > between the aluminum head and the cast iron block (and steel bolts) can > both cause distortion of the head, cracks, and a crushed head gasket. > > If it didn't blow steam, just replace the alternator and belt and see > what happens. Symptoms of a failed head are loose head bolts, coolant > in the oil (or combustion chambers = white smoke), or oil in the > coolant tank. You may also get gas bubbling up in the coolant tank > from a cracked head or at blown head gasket. A bad gasket on that car > will also start to leak oil out the rear right corner. > > You may be OK, you will just have to see. > > Peter > > > ___ > http://www.okiebenz.com > For new parts see official list sponsor: http://www.buymbparts.com/ > For used parts email [EMAIL PROTECTED] > > To Unsubscribe or change delivery options go to: > http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com > ___ http://www.okiebenz.com For new parts see official list sponsor: http://www.buymbparts.com/ For used parts email [EMAIL PROTECTED] To Unsubscribe or change delivery options go to: http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] overheating engines
Glycol raises the boiling point of the coolant to around 240F, pressure cap raises the BP to around 260F. However, if the coolant is not circulating, the head can get really hot, and both differential expansion of the parts of the head and the difference in expansion between the aluminum head and the cast iron block (and steel bolts) can both cause distortion of the head, cracks, and a crushed head gasket. If it didn't blow steam, just replace the alternator and belt and see what happens. Symptoms of a failed head are loose head bolts, coolant in the oil (or combustion chambers = white smoke), or oil in the coolant tank. You may also get gas bubbling up in the coolant tank from a cracked head or at blown head gasket. A bad gasket on that car will also start to leak oil out the rear right corner. You may be OK, you will just have to see. Peter ___ http://www.okiebenz.com For new parts see official list sponsor: http://www.buymbparts.com/ For used parts email [EMAIL PROTECTED] To Unsubscribe or change delivery options go to: http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] overheating engines
I don't have the info at hand but to what degree does coolant raise the boiling point? I am trying to dig into the memory banks to remember automotive cooling systems 101 and the effect of the radiator cap in raising the boiling point. This is called the pressure cooker principle, where temps of 100d Celcius+ are achieved by raising the pressure within the cooker. So yes a hot motor 100+ will have more pressure in the system than a motor at 85d C but if it is enough to cause damage is hard to tell. However given the fact that the radiator cap did not blow (unless it is the wrong one) is a indicator that no damage was done but it is a 20 year old motor and just that little bit of extra pressure could perhaps maybe in some circumstances done something which may cause problems further down the road but personally I would just keep going. However we are all just guessing and no one can give you a definite answer in regards to damage done. It's like asking how a auto box will last once it starts flaring in the shifts, my Mum's lasted years and is only now starting to die properly. Sure we could have fixed it when the first signs of trouble started but we didn't. - Original Message - From: "OK Don" <[EMAIL PROTECTED]> To: "Mercedes Discussion List" Sent: Thursday, September 27, 2007 11:25 AM Subject: Re: [MBZ] overheating engines > That's the key - did it hit the 120 mark and that's as hot as it got, > or did it exceed the range of the gauge, and actually was much hotter? > > On 9/26/07, Zoltan Finks <[EMAIL PROTECTED]> wrote: >> Good word. No, no steam and the engine really didn't even feel overly >> hot when I opened the hood. >> >> >> Brian >> ___ http://www.okiebenz.com For new parts see official list sponsor: http://www.buymbparts.com/ For used parts email [EMAIL PROTECTED] To Unsubscribe or change delivery options go to: http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] overheating engines
That's the key - did it hit the 120 mark and that's as hot as it got, or did it exceed the range of the gauge, and actually was much hotter? On 9/26/07, Zoltan Finks <[EMAIL PROTECTED]> wrote: > Good word. No, no steam and the engine really didn't even feel overly > hot when I opened the hood. > > > Brian > > On 9/26/07, Hendrik Riessen <[EMAIL PROTECTED]> wrote: > > That is why there are radiator pressure caps fitted to cars, so unless the > > wrong cap is on the engine the expanding coolant theory is a bit shaky. Was > > there any steam action? Is the correct cap on the expansion tank (it should > > be stamped on the cap, 120 I think)? > > If there was an expulsion of steam I would say yes you are in the poo poo > > but if it just got up the 120 mark then you should be pretty right, however > > every engine is different and just because old cast iron engines can be > > overheated for a half a day without ill effects does not mean a aluminium > > and cast iron engine is the same. > > Remember that MB engines are designed to go up to 110 on a regular basis and > > as such a little spike to 120 should not be a killer. > > However sensible design would state that a warning light in conjuntion with > > a buzzer would be prudent but then how are they gonna make money from cooked > > engines? -- OK Don, KD5NRO Norman, OK "There are three kinds of lies: lies, damn lies, and statistics." -Benjamin Disraeli '90 300D, '87 300SDL, '81 240D, '78 450SLC, '97 Ply Grand Voyager ___ http://www.okiebenz.com For new parts see official list sponsor: http://www.buymbparts.com/ For used parts email [EMAIL PROTECTED] To Unsubscribe or change delivery options go to: http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] overheating engines
Good word. No, no steam and the engine really didn't even feel overly hot when I opened the hood. Brian On 9/26/07, Hendrik Riessen <[EMAIL PROTECTED]> wrote: > That is why there are radiator pressure caps fitted to cars, so unless the > wrong cap is on the engine the expanding coolant theory is a bit shaky. Was > there any steam action? Is the correct cap on the expansion tank (it should > be stamped on the cap, 120 I think)? > If there was an expulsion of steam I would say yes you are in the poo poo > but if it just got up the 120 mark then you should be pretty right, however > every engine is different and just because old cast iron engines can be > overheated for a half a day without ill effects does not mean a aluminium > and cast iron engine is the same. > Remember that MB engines are designed to go up to 110 on a regular basis and > as such a little spike to 120 should not be a killer. > However sensible design would state that a warning light in conjuntion with > a buzzer would be prudent but then how are they gonna make money from cooked > engines? > > - Original Message - > From: "Curt Raymond" <[EMAIL PROTECTED]> > To: "Diesel List" > Sent: Thursday, September 27, 2007 8:49 AM > Subject: Re: [MBZ] Getting taken by mechanic currently > > > > Remember what happens when you overheat the engine: > > The coolant turns to steam. The steam takes up a LOT more space than the > > water does. In an earlier post I'd said like 6x I did a little search and > > apparently it's more like 1500x!!! > > That much extra pressure has to go somewhere, blowing the headgasket is a > > really common result. > > I don't think the head cracks from pressure though, I think the head > > cracks from the temperature differential through its mass. The hottest > > part of the head, the combustion chamber, wants to enlarge from the heat > > of combustion. Thats normally held in check by the coolant which wicks > > that heat away. Once the coolant is steam the heat concentrates and now > > the lowest part of the head wants to expand. Unfortunately its connected > > to the rest of the head which is heating up more slowly and doesn't want > > to expand or doesn't want to expand as quickly. Thats when you get cracks. > > > > Overheating is NEVER good. > > > > -Curt > > > > ___ > http://www.okiebenz.com > For new parts see official list sponsor: http://www.buymbparts.com/ > For used parts email [EMAIL PROTECTED] > > To Unsubscribe or change delivery options go to: > http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com > ___ http://www.okiebenz.com For new parts see official list sponsor: http://www.buymbparts.com/ For used parts email [EMAIL PROTECTED] To Unsubscribe or change delivery options go to: http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] overheating engines
That is why there are radiator pressure caps fitted to cars, so unless the wrong cap is on the engine the expanding coolant theory is a bit shaky. Was there any steam action? Is the correct cap on the expansion tank (it should be stamped on the cap, 120 I think)? If there was an expulsion of steam I would say yes you are in the poo poo but if it just got up the 120 mark then you should be pretty right, however every engine is different and just because old cast iron engines can be overheated for a half a day without ill effects does not mean a aluminium and cast iron engine is the same. Remember that MB engines are designed to go up to 110 on a regular basis and as such a little spike to 120 should not be a killer. However sensible design would state that a warning light in conjuntion with a buzzer would be prudent but then how are they gonna make money from cooked engines? - Original Message - From: "Curt Raymond" <[EMAIL PROTECTED]> To: "Diesel List" Sent: Thursday, September 27, 2007 8:49 AM Subject: Re: [MBZ] Getting taken by mechanic currently > Remember what happens when you overheat the engine: > The coolant turns to steam. The steam takes up a LOT more space than the > water does. In an earlier post I'd said like 6x I did a little search and > apparently it's more like 1500x!!! > That much extra pressure has to go somewhere, blowing the headgasket is a > really common result. > I don't think the head cracks from pressure though, I think the head > cracks from the temperature differential through its mass. The hottest > part of the head, the combustion chamber, wants to enlarge from the heat > of combustion. Thats normally held in check by the coolant which wicks > that heat away. Once the coolant is steam the heat concentrates and now > the lowest part of the head wants to expand. Unfortunately its connected > to the rest of the head which is heating up more slowly and doesn't want > to expand or doesn't want to expand as quickly. Thats when you get cracks. > > Overheating is NEVER good. > > -Curt > ___ http://www.okiebenz.com For new parts see official list sponsor: http://www.buymbparts.com/ For used parts email [EMAIL PROTECTED] To Unsubscribe or change delivery options go to: http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
