Moderator: Luke
Jim Archer wrote:Pressure cap test won't tell you much - it's holding pressure. Your issue is a build-up of system pressure that is greater than the normal expansion/contraction of the coolant in use.
Is the waterpump actually pumping? It's cold enough at the mo that you'd have to drive quite hard for a dodgy pump to show itself in the motor overheating.
Air leak on the suction side of pump? Though it should purge itself into the header tank.
EGR intercooler? These can cause pressure build-up, but you'll also lose coolant into the exhaust - giving sweet smelling exhaust as the exhaust run heats up.
Does the cooling system pressurise quickly from cold? With boses going firm before they get warm? Probably the 1 sure sign of a leaking headgasket.
Jim
Transitdickeye wrote:Thanks Jim,
I hadn’t thought of the water pump, suppose it could be worth checking to make sure that it’s running properly.
I don’t believe I’m losing coolant, but won’t rule out EGR.
Every morning the system is pressurised more than normal, even If it’s left 2 days and cold it’ll still be pressurised.
The problem has also caused my truck to not run at the proper temperature, I had to do a forced regeneration to it to clear the DPF as this quickly blocked due to the truck not being hot enough to perform a regeneration of its own.
I’ve changed the thermostat with a genuine Ford one so don’t think it’s the sensor that’s the problem.
It could be all linked but I’m abit lost as what it could do now.
The hoses don’t go firm before warm, they’re quite flexible and then get hot once the engine warms up.
Somewhere somehow the truck isn’t reaching temperature and my coolant system is overly pressurised.
Thanks for the response!
tranmx2 wrote:Thanks for the reply Knobby.
As yet I have not seen/found the EGR cooler. It is supposedly at the back of the engine. From underneath looking up to the back of the engine can see a rusted pipe connector.
- You're thinking too much about problems which don't really occur - like holes in the ground which are not there however one falls into them.
However/Whatever getting closer to the whatever the problem is. Now know what some of the pipes are on the system. Using Forscan gives some more info'.
No sigh of steam in the exhaust.
I am about to embark on a routine of checks to try and find the whatever.
It is now winter and I don't want to have to work outside.
the coolant travels around the system too quickly to get large pockets of trapped air. Have not known trapped air to move out of a pocket unless vented. The pocket needs to be prevented from forming. Several small pockets add up to a big one.
The pressure is retained - if the pressure was from the heat/expansion of the coolant the pressure could drop when the coolant cools.
The pressure could be retained by the flexible pipes and air traps. Loss of coolant to the air pockets and flexible pipes - coolant level is not returned when the pressure is released. Coolant could replace air that was trapped.
I had hoped it is related to the EGR cooler but as yet I can't find it. Coolant could be lost via the EGR cooler but the exhaust gas pressure is less than the coolant working pressure unless when cold and with no pressure in the coolant system exhaust gas can enter the coolant system and so pressurise it. If the coolant pressure is 0 the pressure from the exhaust cannot get the coolant pressure above 3 psi unless the exhaust is blocked but then what pressure can be achieved?
DP DPF is usually . 6 kPa = 0.08 psi at idle - it has been seen at 18.00 kPa = 2.6psi. Pressure in the coolant is higher. When a test was done the rad cap did lift at about 30 psi. Should be 19 to 22 psi.
There being no air in the coolant system. The level is just above max. The coolant cold at start. Engine heats up coolant = enclosed system pressure increase. If pressure above 19 psi and pressure release occurs some coolant is lost as steam. Engine stopped. Coolant cools to cold. Could result in a vacuum in the system due to coolant loss - flexible pipe collapse.
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