So the oil dipstick tube popped out during removal of the alternator bracket, I just can't get it back seated and bolted without removing the exhaust system.
I want to test the van 1.6hdi diesel engine. What effects would having no tube in have, would this create an air leak for example?
Most vehicles have a PCV system that sucks a small amount of fresh metered air through the crank case to ventilate combustion gasses that have got past the piston rings. The fumes are then pulled into the inlet manifold and burned in the cylinders.
If you leave the dipstick out, some unmetered air can then be pulled in. This would be an issue with a petrol/gas engine since the fuel/air needs to be correctly metered. A diesel however is a lean burn engine, so this shouldn’t be an issue.
Air being sucked in will be bypassing the air filter and any dirt/dust will end up in your engine oil, so that is something to consider.
I would also be surprised if the oil that will be splashing around in the crank case doesn’t find its way out of the hole where the dipstick tube was fitted.
I would take the time to reinstall the dipstick tube. You could possibly end up ruining the entire engine by contaminating the oil with dirt and water.
If you insist on leaving the dipstick tube out, I would at least plug the hole to make sure no debris or water contaminates the oil system.
