Checking for Leaks
The first thing I do if I don’t seen an obvious coolant leak on a vehicle with an overheat condition is bleed the cooling system. As pointed out earlier, many times the air is the result of improper service, or sometimes the coolant just gets low enough to develop an air pocket. Bleeding that air out often cures the problem. If you see an obvious coolant leak, then by all means, repair it, bleed the system, and recheck for the overheat condition. If it’s not obvious where the leak is, there are methods you can employ to find it. These methods are outlined in this video, along with many of the topics covered in this article.
Much of what I’m about to cover in this next section is covered in the video, but I’ll go over it again just to be thorough.
The next step after you’ve purged any air from the system is to check for leaks. The best way to do this is with a pressure tester.
This tool pressurizes the cooling system and forces the coolant to leak if there is a place for it to escape. Often you can find those pesky small leaks that are difficult to spot with this method. Another method is to just put your eyes on the engine and surrounding area. Often when coolant leaks, it leaves a nice stain around the area where it leaks, which can be easy to spot if you’re lucky. Once you’ve found the leak, repair it, bleed the system, and recheck for the overheat condition.
If you don’t find any external leaks, it’s time to get creative. Also, don’t forget to check under the dash for coolant leaks when pressure testing. A leaking heater core can cause this, and since it’s buried in the HVAC system, it can be hard to spot a leak from this area. If you notice wet carpet on the passenger-side floorboard, or your windshield fogs up and is perhaps coated with a greasy residue, you could have a heater core failure. I’ll cover this more in the HVAC article.
Video Title: Checking for Leaks – What to Do When Your Engine Overheats – EricTheCarGuy Video Description: In this topic you will learn about how Check for Leaks and What to Do When Your Engine Overheats. Thumbnail: http://www.ericthecarguy.com/images/faq_buttons/Large_FAQ_Images/engine-overheat-Icon-large.jpg