| Author | Message | ||
     Pedro Gomes Experienced User Username: portamno Post Number: 46 Registered: 2-2018 |
Dear colleagues: My Mulsanne S was stopped for 4 years....Then, with great tips and enormous support from you, suspension trouble, warped top of the dasboard, idling etc. was all sorted out. So, FINALLY I have driven the car. But, ALAS, i checked that temperature gauge was going up, not really to the red line, but warmer than usual...It was a very warm day, and when fans started up, the gauge did show "some" cooling....Still, I took the car to the mechanic just to BE SURE....Well, when I stopped the car, and a fter a few moments, I could see that coolant was dripping from the the overflow tube....Car was left at the mechanic to check. Now, everytime the mechanic starts the car, and once it gets warm, the coolant comes out of the overflow tube.... What could it be? a "stuck" thermostat? A non functioning or intermitent water pump? I have never had that problem before.... Can you please help? Best Regards Pedro | ||
| richard george yeaman Grand Master Username: richyrich Post Number: 994 Registered: 4-2012 |
Hi Pedro sounds a bit ominous. Richard. | ||
| Pedro Gomes Experienced User Username: portamno Post Number: 47 Registered: 2-2018 |
Hi Richard, But the car is running like a kitten....Ominous? Hope itīs nothing MAJOR? Any suggestions? Best Regards Pedro | ||
| Mark Aldridge Grand Master Username: mark_aldridge Post Number: 562 Registered: 10-2008 |
Pedro, I would change the thermostat and flush the system to start with. Mark | ||
| michael vass Grand Master Username: mikebentleyturbo2 Post Number: 490 Registered: 7-2015 |
Hi ,maybe a compression test would help diagnosis? Mike | ||
| Pedro Gomes Experienced User Username: portamno Post Number: 48 Registered: 2-2018 |
Dear Mark; Dear Michael: I and the mechanic have flushed the system as well as checked the water pump. I believe we have found the culprit, as you can see by the picture of the expansion bottle...See that brown area? It's an indication from the mechanic that somebody has tried to glue it once..... The theory is: The expansion bottle is taking in air, a microscopic breach has opened. This means air is coming in in an otherwise closed cooling circuit. This air is then sent to the radiator. We opened it and saw the liquid "bubbling"....As a consequence the boiling point of the cooling mixture goes down, due to lower pressure....However, it still must go out of the sytem....It does that when car stop, and water pump is not working anymore..... Ordering a new one tomorrow, will get it by the following day. Will let you know how it goes. Best Regards Pedro  | ||
| Omar M. Shams Grand Master Username: omar Post Number: 1628 Registered: 4-2009 |
Dear Pedro These bottles are weak and often fail. Two checks would be my approach after replacing the bottle .first I would take the thermostat out and check that it functions correctly .Secondly I would replace the viscous coupling on the fan. | ||
| Robert J. Sprauer Experienced User Username: wraithman Post Number: 47 Registered: 11-2017 |
"We opened it and saw the liquid "bubbling" I would do a dye test for exhaust fumes in the coolant. | ||
| Omar M. Shams Grand Master Username: omar Post Number: 1629 Registered: 4-2009 |
When the plastic overflow tanks burst - it is often due to the system being over pressured .This happens when the cooling system is pushed beyond its normal operational state .Most of the time this is because the viscous coupling loses efficiency. Very hard to see until its too late .At this stage I would recommend a new viscous coupling as well as a new plastic tank . | ||
| Mark Luft Prolific User Username: bentleyman1993 Post Number: 205 Registered: 10-2016 |
I would suspect a blown head gasket (sorry).  Usually, bubbles in the coolant mean excess pressure in the system from exhaust gasses leaking in from the cylinder. A dye test is recommended. | ||
| Robert J. Sprauer Experienced User Username: wraithman Post Number: 48 Registered: 11-2017 |
The top radiator hose should be easy to squeeze when the engine is running. If it feels firm to squeeze...you likely have too much pressure. Again do a dye test with UV light at the tail pipe and radiator.. Did you check the condition of the oil for coolant contamination? You want to rule out as many causes as possible especially head gasket failure. | ||
| Pedro Gomes Experienced User Username: portamno Post Number: 49 Registered: 2-2018 |
Thank you all for your suggestions: The new expansion bottle has just arrived, and I am off to the mechanic....Will proceed to do that dye test. Hopefully it's not a blown head gasket....We looked carefully at the engine, and it does not appear to have blown the gasket....The car never overheated, it just ran warmer...Will also look at the viscous coupling.... Will let you know Best regards Pedro | ||
| Robert J. Sprauer Frequent User Username: wraithman Post Number: 52 Registered: 11-2017 |
Head gasket issues can be subtle and rarely noticed from the outside so therefore many diagnostics are needed. | ||
| Pedro Gomes Experienced User Username: portamno Post Number: 50 Registered: 2-2018 |
Dear All, At this time, the dye test has been done and there are no gas inflitrations in the system...HOWEVER, the electric fan is not coming on when car heats up....But the thermostat has been taken out, could this be the reason why the electric fan does not start? We have actually been able to turn on the electric fan by direct contact....So there is also the possibility that the heat sensor that turns on the electric fan is damaged...But it was working just fine a couple of fays ago! The new expansion bottle has been installed, and it works just fine. But the car, once it heats up, it does not cool down. I dont let it go to red though. This is VERY FRUSTRATING! Going back to the mechanic now. Best Regards Pedro | ||
| Robert J. Sprauer Frequent User Username: wraithman Post Number: 53 Registered: 11-2017 |
You must have a thermostat. The coolant is running too fast in your radiator and not allowing it to properly cool. Get the proper thermostat for your car and not a generic one. | ||
| Pedro Gomes Frequent User Username: portamno Post Number: 51 Registered: 2-2018 |
Hi Robert: Thank you for your comment. The mechanic had taken the thermostat away, to check if it was "stuck". So the trials were WITHOUT it. Tomorrow morning, we shall install it again. HOPEFULLY, that will be the end of trouble! Best Regards Pedro | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 1944 Registered: 9-2004 |
Don't like the sound of liquid bubbling. A cylinder leakage test would tell you a great deal first within the engine, thermostat fitted or not. | ||
| Pedro Gomes Frequent User Username: portamno Post Number: 52 Registered: 2-2018 |
Hi everybody! Well, it seems that the potential overheating issue is resolved. The car runs "warm" meaning the needle is not really centered in the middle of the gauge, rather a bit to the right. And in a warm day, or going uphill, it even moves a little more to the right. But it never leaves the white "safety area"....I have tested and tested...The car is running like a dream, and yet I am still a little "bothered", as before the needle hovered right in the middle of the gauge, regardless of going uphill or downhill. Now if "pushed" it will go almost to the end of the white area, and then it slowly moves to the left. Not entirely satisfied yet, will probably change the thermostat also.... Best Regards To ALL | ||
| Christian S. Hansen Grand Master Username: enquiring_mind Post Number: 855 Registered: 4-2015 |
We are interested to know what was necessary to effect the resolution. Do tell? | ||
| Robert J. Sprauer Frequent User Username: wraithman Post Number: 55 Registered: 11-2017 |
Your radiator is losing efficiency due to age. A radiator boil out and block flush will help. A "radiator sock filter" can be place in the top hose to capture debris after the flush. You will be amazed how much debris moves around in the cooling system. | ||
| Pedro Gomes Frequent User Username: portamno Post Number: 53 Registered: 2-2018 |
Dear Christian: Thank you for your comment: The main "culprit" was the expansion bottle, which had a microscopic tear....And then some mechanic "fixed" it, by gluing it...You can see in the picture I have posted right at the beginning. So air was getting into the system, and once the car stopped, plenty of coolant just gushed out of the system....That is now fixed. However, what Robert is suggesting, that the radiator is losing efficiency due to age is MAKING A LOT OF SENSE to me....I hate that the needle goes towards the right....Am I a perfectionist? NO! Just that owning a Bentley, I have learned the hard way that better be preventive, than to "lighten your wallet drastically".... Best Regards Pedro | ||
| Pedro Gomes Frequent User Username: portamno Post Number: 54 Registered: 2-2018 |
Hi Robert: Thank you for your comment. Please excuse my lack of knowledge but what is a "radiator boil out"? and a "block flush"? Best Regards Pedro | ||
| Robert J. Sprauer Frequent User Username: wraithman Post Number: 57 Registered: 11-2017 |
Thank Pedro, All water has minerals unlike distilled. The minerals leave the waterspots on your glass fixtures in your home, but they are not welcome in a cooling system since they group together and attach to iron, aluminum, brass etc. After awhile they obstruct waterways much like plaque does in our arteries so you add an agent to dissolve the buildup. It is very common in the radiator business to immerse the radiator in a hot tank for awhile to "boil it out". Flushing the block is done with a hose arrangement thru the lower radiator hose, running the engine to flush out debris. The radiator should be isolated so you're not polluting it from the engine debris.This is a messy procedure since the water exit is the top hose connection so it must be directed away from the car. | ||
| Pedro Gomes Frequent User Username: portamno Post Number: 55 Registered: 2-2018 |
Dear Robert: Thank you very much for your wonderful explanation. Could not be better explained! I will proceed to do it. Yesterday, went for a drive, the needle was going towards the right, especially on hills, and then on flat roads would slowly come back towards the middle, but a still a little to the right....I drove about 100 kms...When I got home, did not turn off car immediately, and needle went all the way to the right white (safe area), and stayed there for the 10 minutes I let the engine run.... And the electric fans are not turning on...I know they are OK as I have turned them on thru a direct connection. Before, the can would run with the needle in the middle of the gauge regardless of going up or down a hill, warmer or colder weather. So, I am replacing the thermostat (it's about 5 yrs old and the car did not run for about 4 years) as well as sensor coolant temperature....I believe it's this sensor that "orders" the electric fans to run, should the engine reach a certain temperature. Hope this will solve the issue. What do you think? I have checked the the coolant is not mixing with oil, and there are no leakages. It's very frustrating to drive the car always looking at the heat gauge.... Hopefully, above replacements will fix it once and for all! I cant think of anything else. Best regards Pedro | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 1952 Registered: 9-2004 |
Pedro, for the fans not working first check out the fan relay for operation. | ||
| Jeff Young Grand Master Username: jeyjey Post Number: 376 Registered: 10-2010 |
Take the plug off the Otter switch (the coolant temp sensor) and short out the contacts. If the fan comes on then the Otter switch is faulty; if not then it's something else. | ||
| Omar M. Shams Grand Master Username: omar Post Number: 1641 Registered: 4-2009 |
Dear Pedro, On the 8th August I proposed you look at the viscous coupling. I still think you need to look at that. When you remove it see if there is any trace of oil around the centre. If there is then the unit has failed. These things fail in a partial way when they go. It all appears to be working fine but at the time of need they cant perform. If your unit has no traces of oil then it may be ok. But honestly speaking - this is where i would look after fixing the electric fans. The electric fans only assist. The biggest load is on the engine fan. In a normal car the electric fans can fail and the car never overheats - because the main fan can cope with the load (if the coupling has not failed). | ||
| Jeff Young Grand Master Username: jeyjey Post Number: 377 Registered: 10-2010 |
Omar speaks wise words. The principal purpose of the electric fans is to keep air moving over the A/C condenser when the car is at a stand-still. Here's another thought: any chance someone removed the cowling around the radiator? If it's not there the fan can suck air in at the sides rather than through the radiator fins. http://www.flyingspares.com/shop/media/catalog/category/Radiator_Expansion_Tank_from_VIN_1001_to_8323_.jpg | ||
| Pedro Gomes Frequent User Username: portamno Post Number: 57 Registered: 2-2018 |
Dear ALL Colleagues: Problem is completely solved! This past week-end, I went thru all your comments and suggestions....Furthermore I studied other cases, must have spent at least 6 hours doing research... Then I came across an article "Thermostat issues and Selection by Don Elliot and Phil Birkland, which you can easily locate. Otherwise, as I printed the article, I can scan and send it. On that article, the indicated thermostat, UE 36600, which Crewe suggested that it should be replaced every 2 years came under heavy criticism....As it's made entirely of stainless steel, and I quote "from a metallurgical standpoint, sliding stainless steel on stainless steel risks eventual galling. Galling is a process where microscopic transfer of metal from one surface to another occurs until the surfaces become roughened up and they eventually stick together" End of Quote. Well, my (old) thermostat was more than 6 years old.... Mechanic took it out, could not really see it was "damaged" or not, but I replaced it with part number PG58252PA....This has a stainless steel middle sliding rod, but the rest is made of COPPER...So, No galling. Took car out for a hard test yesterday, on a very warm day, in the 90's....On highway, at about 120 kms, needle just a little to the right of the middle white band, on hills it went a little more towards the end of the white band, but much further away than with the old thermostat. FURTHERMORE, when i stopped the car and let it idle the Needle went precisely to the location where it was before, in another words, it cooled down. Finally have also read that those auxiliary fans seldom come on, as their turn-on temperature is 110š centigrade. On a hot day, the regular temperature is around 102 centigrade.... So this case is CLOSED! I THANK YOU ALL FOR THE TIME YOU HAVE TAKEN! Anything I can do for you in sunny Portugal, please contact me. lofotenfish.portugal@sapo.pt warmest Regards Pedro |
