I had coolant dripping behind my Northstar engine. I borrowed a pressure tester for the cooling system, and I could hear a hiss behind the engine, at the height of the head gasket. I put dye in the coolant to look for the leak, but saw nothing on the engine. I got one of those blue liquid testers, and after I pumped it a lot the blue took on a yellow tinge. I took the car to my mechanic after I saw what it takes to deal with a Northstar head gasket, and told him I was sure it was the head gasket. He called later that day and said it was just my coolant reservoir leaking. The reason the blue liquid was turning yellow was that I was sucking some of the dyed coolant into the tube. What a blessing to have an honest, capable mechanic for the jobs I can't do myself. I bought him and his whole shop lunch.
My son's car was over heating. The first shop change the thermostat. The second shop, said everything was wrong and had a huge list adding up to over $3,600. It was a head gasket and I use the blue liquid tester. Some cars are just prone to head gasket failure after a given amount of miles, due to their design.
Schroeders box had a vehicle with a small leak . He did not have a gas analysier . He used cylinder leak down on the suspect cylinder and found bubbles in over flow tank . That gas analysis is awesome
Thats the way i have done for decades.but my new favorite now is differential pressure transducer and a scope,will pinpoint exact cylinder and can do on load and idle
Always appreciate your no nonsense, cut, and dried, evaluations and solutions! I am an old-school mechanic starting out in 1974 sometimes it was very easy to detect and gasket failure but sometimes the small ones were very difficult to find... thank you
Scope with a pulse sensor can be used as well. I have even triggered off one of the coils and you can figure out which bank is the bad gasket. Still replace both, but nice to know so you can inspect the gasket when you’re performing the repair
I always thought it was strange that the analyzer probe could sit in the muffler pipe and absorb moisture into them from the exhaust but unable to handle any amount of coolant into them. Great vid thanks!
Dear Sir, it is as well very important to make a cooling system pressure test, as well as check the radiator for clogging by uplifting it from car and block the bottom hase outlet, fill it with tap water and check for adequate flow. Also some cars like some Mitsubishis can have a frayed water pump impellar and some other brands can have a plastic water pump impellar that would be eroded. Sometimes people will unknowingly use tap water that could potentially lead to such overheat in extreme summer conditions. You know sometimes in your case where the engine is smooth with no mix of oil/coolant and no apparent bubbling in the coolant when you open the radiator cap, and due to economic situation, the car could live for so many years provided that the client check his oil and coolant daily. This did happens (at my end of the world) ) on a variety of Japanese and American brands, but you should even in your case remedy the root cause of overheating before relplacing the headgasket. Also sometimes a leakdown tester can prove which cylinder is bubbling to the radiator cap so as to imform the machine shop accordingly. Also, a boroscope could show a tiny green bubble into the cylinder provided that the owner uses a coolant. Take Care. John
Thank you, as always, for your clear explanations and showing the way a high-end shop would do things. I also want to say, the camera operator does a consistently good job. One question that doesn't actually matter but... is the liquid (in the 3rd option) reacting to CO2 or hydrocarbons or something else? I noticed it says "CO2 Leak detector" -- but obviously it will react according to the liquid inside, not what the plastic instrument has written on it. Thanks again, Professor!
Thinking the HC readings ate jumping around because of firing order. When the cylinder(s) near the head gasket leaking are coming up on compression it's pushing the HC's & they they get lower until that cylinder comes around again.
Had a Toyota High lander. Always had a coolant odor after driving. Never could find a leak. And needed coolant added after a thousand miles or so. The thought of head gasket never entered my mind. One day the failure was catastrophic and non- repairable. So, if you smell coolant and can’t find a leak… you’re losing it thru the exhaust. That’s where I think I was getting the odor from. There was never a residue under the oil cap, or evidence of crankcase contamination.
All 3 test are valid but their is a but what if the vehicle has an egr cooler that is blown those test will show positive for a blown head but its not its that
You said the tip of that first probe should never get into moisture or get wet, but you also said it goes in the tailpipe. How does that work when so much water comes out of a cars tailpipe?
This would certainly lead you in the right direction but you’d have to do further testing to make sure your data isn’t caused by rings/valve seats. The tests shown here 100% points to a headgasket.
The cheapest way to preliminarily test is to pop the radiator cap on a cold engine. If air pops out at you then you know you either have a bad head gasket or potentially a cracked EGR cooler... I think gas analyzing is kinda outdated at least for new cars. EGR coolers internally leak and will introduce combustion gas into the cooling system. The best method that is cheaper then your first two tools would contend for a borescope, followed by a cylinder leak down test.
