Overheating & coolant levels
Posted: Mon May 23, 2016 11:08 am
Hi,
Please forgive me if this is the kind of post typical of Bongo owners who don’t know their engines and if some of you are rolling your eyes and thinking “inevitable” when reading! I have a 1996, 2.5 turbo diesel, 2 wheel drive, with 108 000 miles on the clock. I’ve had it about 15 months, I’ve done about 20 000 miles in it and I knew nothing about engines or car maintenance when I purchased. However, I now want to learn what is necessary to keep my van in the best possible condition for as long as possible. I have, for example, been taking care to treat the rust on the wheel arches.
Anyway, the other day I drove a few miles, picked up my son, re-started the engine and it cut out as if it had stalled. I was shocked as it has never done this before. I re-started and after about fifty yards I could see the temperature gauge rising. I pulled over as soon as it was safe to do so (a few hundred yards down the road). I lifted up the bonnet and coolant was spurting out of the header tank. After waiting for the engine to fully cool down I tried to drive it the 3-4 miles to home. It overheated again, after going uphill, so I stopped and waited (this time I had the sense to top up the header tank when it was cooled down) and then I got home with no overheating. I spoke to my mechanic on the phone (he is 34 miles away) and quickly renewed my RAC membership which had just expired. As the coolant level in the header tank now didn’t appear to be dropping, and there was no sign of any ‘white deposits’ in my oil and because my heater was working fine he suggested I drive it another few miles to see if it overheated again (he wanted me to drive to a place in town where they would test the header tank for emissions so we could ascertain if the cylinder heads had gone). It overheated again! After waiting ages I got it home without it overheating and the next day I called out the RAC.
The guy from the RAC tested for emissions in the header tank, there was no reading. He couldn’t see anything wrong with the radiator or any leak in the cooling system. I showed him the pipe leading into the head gasket (that I check after reading this article - http://www.practicalmotorhome.com/advic ... yers-guide) which was all fine, and there was still no sign of anything wrong with oil. We bled the coolant system (him assuming there was airlock in the system) and then turned the engine over, no overheating, we upped the revs, no overheating, I drove a couple of miles, no overheating. After three hours he left, happy that the van was at least OK for me to drive to the garage. I am booked into the garage on Monday (I need an oil change, a seat fitting and the underneath being re-sealed as well). I have driven the van twenty miles since. The engine is sitting at its normal temperature (just below half way on the gauge), the coolant level is not falling and the oil is showing no sign of any deposits or anything odd and the heaters are working fine. I suspect that when I go to the garage the mechanic will perhaps not be able to diagnose what the problem was, as the man from the RAC was also slightly perplexed. Also when I first bought the vehicle last year, it overheated once shortly after purchase – I topped up the header tank and it never happened again. I took it to the mechanic who checked it over, but was ultimately unsure of why it had happened, other than there was probably some air trapped in the cooling system. He was confident the cylinder heads had not gone after checking for emissions in the header tank. I checked the coolant level regularly, but it never again had dropped when I checked it. At the time of the overheating this week, I must admit I had grown complacent, and had not checked the coolant level in about four weeks.
The man from the RAC wondered if the cylinder heads had gone (causing a slow leak in the cooling system), but had gone in a place where it wouldn’t be causing emissions into the header tank or for it to show in the oil. He was just guessing though. He did say it would cost a lot to open them up and examine.
I see from reading these forums that a lot of people recommend fitting a coolant level alarm. I can see now that this is sound advice, but it does raise the question – Why would the coolant level drop other than the cylinder heads having gone? Why is it stable for a long time and then drops? If I fit an alarm and the level drops, do I just top up and watch, or do I take it straight to a garage? Should I learn how to bleed the coolant system (I watched the Youtube clips and at first I thought it looked too complex for me, but after doing it with the RAC man I realised it wasn’t too difficult) and do it every now and again? Should I ask the mechanic to take off the cylinder heads and check them even if we are still getting no emissions in the header tank?
Apologies for the overly long post by the way. Thanks for reading and cheers for any advice,
Michael.
Please forgive me if this is the kind of post typical of Bongo owners who don’t know their engines and if some of you are rolling your eyes and thinking “inevitable” when reading! I have a 1996, 2.5 turbo diesel, 2 wheel drive, with 108 000 miles on the clock. I’ve had it about 15 months, I’ve done about 20 000 miles in it and I knew nothing about engines or car maintenance when I purchased. However, I now want to learn what is necessary to keep my van in the best possible condition for as long as possible. I have, for example, been taking care to treat the rust on the wheel arches.
Anyway, the other day I drove a few miles, picked up my son, re-started the engine and it cut out as if it had stalled. I was shocked as it has never done this before. I re-started and after about fifty yards I could see the temperature gauge rising. I pulled over as soon as it was safe to do so (a few hundred yards down the road). I lifted up the bonnet and coolant was spurting out of the header tank. After waiting for the engine to fully cool down I tried to drive it the 3-4 miles to home. It overheated again, after going uphill, so I stopped and waited (this time I had the sense to top up the header tank when it was cooled down) and then I got home with no overheating. I spoke to my mechanic on the phone (he is 34 miles away) and quickly renewed my RAC membership which had just expired. As the coolant level in the header tank now didn’t appear to be dropping, and there was no sign of any ‘white deposits’ in my oil and because my heater was working fine he suggested I drive it another few miles to see if it overheated again (he wanted me to drive to a place in town where they would test the header tank for emissions so we could ascertain if the cylinder heads had gone). It overheated again! After waiting ages I got it home without it overheating and the next day I called out the RAC.
The guy from the RAC tested for emissions in the header tank, there was no reading. He couldn’t see anything wrong with the radiator or any leak in the cooling system. I showed him the pipe leading into the head gasket (that I check after reading this article - http://www.practicalmotorhome.com/advic ... yers-guide) which was all fine, and there was still no sign of anything wrong with oil. We bled the coolant system (him assuming there was airlock in the system) and then turned the engine over, no overheating, we upped the revs, no overheating, I drove a couple of miles, no overheating. After three hours he left, happy that the van was at least OK for me to drive to the garage. I am booked into the garage on Monday (I need an oil change, a seat fitting and the underneath being re-sealed as well). I have driven the van twenty miles since. The engine is sitting at its normal temperature (just below half way on the gauge), the coolant level is not falling and the oil is showing no sign of any deposits or anything odd and the heaters are working fine. I suspect that when I go to the garage the mechanic will perhaps not be able to diagnose what the problem was, as the man from the RAC was also slightly perplexed. Also when I first bought the vehicle last year, it overheated once shortly after purchase – I topped up the header tank and it never happened again. I took it to the mechanic who checked it over, but was ultimately unsure of why it had happened, other than there was probably some air trapped in the cooling system. He was confident the cylinder heads had not gone after checking for emissions in the header tank. I checked the coolant level regularly, but it never again had dropped when I checked it. At the time of the overheating this week, I must admit I had grown complacent, and had not checked the coolant level in about four weeks.
The man from the RAC wondered if the cylinder heads had gone (causing a slow leak in the cooling system), but had gone in a place where it wouldn’t be causing emissions into the header tank or for it to show in the oil. He was just guessing though. He did say it would cost a lot to open them up and examine.
I see from reading these forums that a lot of people recommend fitting a coolant level alarm. I can see now that this is sound advice, but it does raise the question – Why would the coolant level drop other than the cylinder heads having gone? Why is it stable for a long time and then drops? If I fit an alarm and the level drops, do I just top up and watch, or do I take it straight to a garage? Should I learn how to bleed the coolant system (I watched the Youtube clips and at first I thought it looked too complex for me, but after doing it with the RAC man I realised it wasn’t too difficult) and do it every now and again? Should I ask the mechanic to take off the cylinder heads and check them even if we are still getting no emissions in the header tank?
Apologies for the overly long post by the way. Thanks for reading and cheers for any advice,
Michael.