Charles Morris: Can you advise what could cause coolant system back pressure. Pressure build up will cause res. tank cap to blow off. Engine shows no overheating but continue to loose anti-freeze. No leaks found when compress. test done. ???
Charles Morris: I am getting back pressure in coolant system. Did compression test & show no leaks. Changed TS & rad.cap. Any suggestions has to why building up pressure?
Numinous: I've always been told to remove all the spark plugs at once and keep cranking until the needle stops rising (usually 6-8 on my Mazdaspeed 3). Supposedly not having the spark plugs in the 3 cylinders you're not testing helps get an accurate reading faster because the starter doesn't have to work against all that extra cylinder pressure.
TheArtistsHeart Studio: well kept shop....reminds me of my life until age 17 when I moved out...my dad was the only mechanic in our small area and all adjacent towns.....I was daddy's girl like no other! !! I spent my days in a pan of gas cleaning his tools,,,playing in sawdust cleaning up spills....he made sure to keep me in modeling and even a couple beauty pageants so I would still have my girly side....but I sure do miss the days I spent with him in that old smelly garage!! he passed away in 2005 and I STILL have people that call asking me " I've got such n such problem do you remember any tricks Mr.Jack used to do to check this? 😄 I think it's cool......... and my apologies, I know my comment is way off in left field for the video topic but seeing how nice ,neat and we'll tooled your shop is just made me think back to working with my dad....
inked420js: nice car bro.
Keisha Smith: What brand of Cooling System Pressure Tester set are you using? I would like to buy what you have. And where online can I find it?
mbdulka: I've recently been chasing a "gremlin" -- my car is pushing coolant at high-boost only .... I've done all these tests:
1. Compression Test = OK 2. Leak Down Test = Ok 3. Radiator Cap Test = 1 of 2 was a bit weak, so got new ones (problem still presisted) 4. No oil in coolant; no coolant in oil 5. UV Dye test into coolant = Ok (no dye in exhaust or anywhere else) 6. Radiator system pressure test (holds pressure to cap) 7. Removed thermostat (looked a bit bent) = didn't solve issue 8. Vacuum system test (holds vacuum) = Ok 9. Videoscoped pistons for leaks/coolant = All ok
Flushed the system good (was pretty clean); put in new thermostat -- used vacuum coolant filler (no air in system) ... used a mix with less distilled water. Last check it didn't push coolant. Even on big boost.
What you might get is a head lifting on boost, but not during idle/cruise -- most of these tests will not show you that unfortuately. Good video.
daniel w: Very informative video ur the man
sam davies: Cool workshop attire!
617k122: Hey Jafro, is it right to leave the plugs in besides the one your testing on ? I was told all should be removed the. Placed into your if wires and grounded so the spark doesn't ark back into the coil pack, also remove your engine fuse for fuel ?
Tim McNeil: good video , thank for the info.
SAL: nice vid
Alan Borjo: I've got a 99 Nissan Altima that has a possible blown head gasket. No smoke or fog exhaust. oil looks good. I changed the antifreeze because it was a rust color and when I refilled it, color changed to rust again. Weird! Any ideas?
SMIT411: Was that any old hand pump you used to test the coolant system? Where did you get the fittings for it? Thanks! Iv a suspected cracked head on my 325i e30...
Philscbx: Good Job Captain - Stumbled on & Im glad I did. 45 yrs of funny car to aircraft - every move - steps of perfection. To critical editing with details - For all others looking on - this is a Class Act.
RbG84: for me i buy a co2 combustion tester and is the best!! no need mount nothing is very fast
Jafromobile: Thank you Kyle! I always appreciate your awesome comments. It's also nice to see you explore my old skool DV videos, too! :D
Kyle Whybrew: You really do nothing less than perfection. A very detailed and accurate video on coolant systems and head health.
Jafromobile: And there you have it...
That's precisely why I boiled over on the dyno. Mine was complicated by a failed overflow system, but once air got in, there you go. Boyle's Law.
Jafromobile: If you are for sure blowing exhaust into the coolant system, it's a safe bet that the head gasket is blown or the head is cracked. Under normal circumstances, that should never happen. It just means that the gasket isn't breached anywhere around the oil return galleries. Aside from overheating, driving it like that can damage the radiator or heater core. Replacing the head gasket is the right fix. A radiator pressure test will expose any other leaks in the coolant system.