 | Home > Puma (Tdci) > Puma pushing out coolant |
 
|
|
|
| andy63 Member Since: 30 Jun 2023 Location: north east Posts: 575  
|
I asked the question a few posts back about defective egr cooler pressurising the coolant system??
What are the symptoms when this happens.. In my head I still keep returning to the point I made in that post about the pressure differences between the two systems.. |
||
16th Jan 2025 7:09am |
|
| andy63 Member Since: 30 Jun 2023 Location: north east Posts: 575
|
No.. not to me ๐ซฃ๐คฃ
Ive never had it stripped but the egr cooler is bolted on to one end of the exhaust manifold.. The egr gases are not under any pressure other than those in the exhaust manifold which fluctuates but will quickly drop and is always open to atmosphere at one end.. The egr system will not be active during high boost conditions in the manifold..and is designed to open under light loads when the manifold pressure will be low due to the induction of air to the cylinders..aided by an electronic throttle flap to further promote the flow of the exhaust gases by creating a restriction and furthur dropping the pressure.. That's more or less how I see it, but all ears for other views..๐ |
||
|
16th Jan 2025 8:34am |
|
| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17501 
|
On a typical modern turbo diesel engine the exhaust manifold pressure will be 1.5 to 2.5 times greater than the inlet manifold pressure. The exhaust manifold pressure is essential to drive the turbo, and is reduced as each restriction in the exhaust system is passed, so between the turbo and cat (or DPF) the pressure will be lower than the manifold, between the cat and silencers lower again, and downstream of the silencers lower still.
It is inevitable that the engine will discharge a much greater volume of exhaust gas than the volume of induction gas, since that is how internal combustion engines work. The compressed induction gas is heated rapidly by the burning of fuel to create a much greater pressure which then expands driving the piston. The exhaust gas is still much hotter and still expanding when discharged from the cylinder, consequently there is far more of it than there was induction gas. The sudden expansion of the exhaust gas to atmospheric pressure is what makes an open exhaust so loud, and on road vehicles this expansion is regulated by the silencer so that it takes place gradually and therefore doesn't create the pressure wave that makes the noise. If there was no exhaust manifold pressure, the EGR could never work, nor could the turbo. In fact, nor could the engine. Could the exhaust pressure expel coolant if the EGR cooler is faulty? Yes, absolutely it could. Remember that the cooler is on the exhaust side of the EGR valve so is always full of exhaust gas whether or not the EGR is working. If the engine is at full boost and relatively high revs the EGR will be shut, the inlet manifold pressure will be perhaps 2 bar above atmospheric (3 bar absolute) and hence the exhaust manifold pressure could easily be 4 to 5 bar above atmospheric (5 or 6 bar absolute), so around 70 psi. This will definitely blow coolant out of the system. This exhaust pressure is also the reason why 2.4 Pumas tend to blow out the gasket between the manifold and the turbo, and the gasket between the head and the manifold. |
||
|
16th Jan 2025 11:14am |
|
| custom90 Member Since: 21 Jan 2010 Location: South West, England. Posts: 20529
|
Could the MAP sensor be caked up and putting out, out of range readings? Worth checking.
Iโve often found the MAF to stay relatively clean, but the MAP is more likely to get dirty, which is to be expected really. Of course it often is never cleaned with any kind of servicing, unless the customer does it themselves which often doesnโt happen either until fault issues. No Guts, No Glory. ๐ฌ๐ง๐ด๓ ง๓ ข๓ ฅ๓ ฎ๓ ง๓ ฟ๐ด๓ ง๓ ข๓ ท๓ ฌ๓ ณ๓ ฟ๐ด๓ ง๓ ข๓ ณ๓ ฃ๓ ด๓ ฟ๐ฎ๐ช๐บ๐ธโฝ๏ธ๐ข๏ธโ๏ธ๐งฐ๐ช |
||
|
16th Jan 2025 12:32pm |
|
| andy63 Member Since: 30 Jun 2023 Location: north east Posts: 575
|
Thanks for that comprehensive reply bw..๐ so it a yes there is sufficient pressure in the exhaust manifold..
I'm surprised..I thought that the pressure of the gases leaving the cylinders would drop very quickly and it was about the high rate of flow created.. I'll look at what figures I have so far with my scope work but I know I don't have anything other than tail pipe traces , but I also know that i have very little restriction in my exhaust system and am surprised at the pressures mentioned.. My max inlet boost would be about 1.5 bar or 21 psi On the dirty map sensor I'm fairly sure I've mentioned before that if the sensor itself if dirty then its likely the manifold port that leads to it's housing is also in a state, and cleaning just the sensor may not be enough.. |
||
|
16th Jan 2025 1:36pm |
|
| stichill99 Member Since: 16 Jul 2024 Location: Scottish Borders Posts: 9
|
I was driving along when I thought their was an electrical fire as a smoke started coming through the dashboard. I quickly pulled over and opened the bonnet to see coolant being forced out of the header tank onto the manifold which was stinking with the anti freeze in it. No fire just coolant on manifold.
I carefully slackened cap with a rag. Cap under extreme pressure. The temp gauge also had rocketed up. When the temp had cooled down drove a mile into a farm and filled up with water. Got a 20litre tub of water and headed home. After 2 stops to allow to cool we made it 12 miles home without overheating. We thought we would replace thermostat down side of engine first as I had been told it can fail easily but it was okay. We then thought it must be cylinder head gasket but after a big stripdown it was perfect looking so what now? We picked up the egr cooler and poured water down the centre water pipe and it poured out where the exhaust gases should go. When we removed the cylinder head their was water in the combustion chamber and before we took engine apart steam was coming out the exhaust! Took the opportunity when all apart to put new clutch in and timing chain and now all good! |
||
|
16th Jan 2025 9:14pm |
|
| stichill99 Member Since: 16 Jul 2024 Location: Scottish Borders Posts: 9
|
 Click image to enlarge Click image to enlarge Click image to enlarge Click image to enlarge |
||
|
16th Jan 2025 9:15pm |
|
| andy63 Member Since: 30 Jun 2023 Location: north east Posts: 575
|
Reading your experience reminds me i have over the few years I've been on here read a few similar accounts..even expansion tanks fracturing..
I had always assumed head gasket failure..๐ซฃ I have a egr cooler and valve still in situ but redundant.. still connected on the coolant system ....perhaps it's time i at least bypassed them even if they are still left in place?? Great photos.. you certainly have access to the right gear for the job..๐ |
||
|
17th Jan 2025 7:11am |
|
| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17501
|
I think it is worth at the very least fitting blanking plates to both ends of the EGR cooler if the EGR is mapped out, as a precaution against this failure.
|
||
|
17th Jan 2025 9:26am |
|
| andy63 Member Since: 30 Jun 2023 Location: north east Posts: 575
|
My preference would be to remove the lot and clear the space a bit..but i understand that may not be sensible๐ซฃ
If i get a chance I'll blank the coolant flow and return pipes to valve and cooler and put a blank in at the exhaust manifold connection to the cooler, if its accessible..๐ I think its blanked at the egr valve outlet at present |
||
|
17th Jan 2025 10:53am |
|
| stichill99 Member Since: 16 Jul 2024 Location: Scottish Borders Posts: 9
|
I spoke to a friend who has a land rover restoration business and asked him what he thought about getting rid of all the egr gubbins and he advised me it can sometimes create more problems than it solves! I would like to see it all got rid of!
|
||
|
17th Jan 2025 12:28pm |
|
| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17501
|
What "problems" did he have in mind?
I will take some convincing that the disbenefits outweigh the benefits, at least as far as the vehicle and owner are concerned. The human race might have a different view I suppose. |
||
|
17th Jan 2025 1:07pm |
|
| andy63 Member Since: 30 Jun 2023 Location: north east Posts: 575
|
I would like folk to be more specific when they say it can cause more problems than it solves..๐ค
And I'm not saying they are wrong but I've run a mk7 transit for at least 5/6 years with a mapped out erg..I did that after I cleaned the inlet side of all the deposits that I think the egr was largely responsible for creating ..I never had any issues as a result.. I'm afraid I'm just to long in the tooth to think its a good idea to recirculate that stuff back into an engine so they can extract the last bit of hp out of the engine and say its still so clean.. they would have been better ceasing the development when it was found they were causing emission problems that could be solved by using an egr valve, And saved us all a lot of hassle..๐๐คฃ With the 2.2 tdci defender the egr goes hand in hand with the dpf..if you get shot of the dpf the egr has to be deleted, but I was told it still had to be connected electrically...I'm still trying to find out exactly why..the transit when deleted could be removed or disconnected..made no difference.. It's a choice you make and if I took it in to a garage for work to be done I'd understand if they refused because I've done the things I've done..but I've done them because I think my engine and use is better for it.. I'm not sure about my green footprint , but I'll guess it's as good as someone buying electric or changing cars every year or so.. Rant over.. ๐๐คฃ |
||
|
17th Jan 2025 1:14pm |
|
| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17501
|
I am personally convinced that deleting the EGR and adding a Provent to the breather circuit is a simple way to extend the life of your engine by a significant amount.
|
||
|
17th Jan 2025 1:57pm |
|
|
|
| All times are GMT |
< Previous Topic | Next Topic > |
Posting Rules
|
Site Copyright © 2006-2025 Futuranet Ltd & Martin Lewis
