skirkland1980 Posted July 24, 2011 Share Posted July 24, 2011 If your engine is overheating here is what to do. First make sure the coolant system is full and no more antifreeze than 50%(ethylene glycol). The best way I've found to fill, and make sure there are no air pockets in the system are to use a vacuum venturi coolant refill tool. They are about $200 but worth it if you make a living fixing cars, as i do. You will also need an infrared thermometer (about$90) or borrow one. Get the engine up to operating temp. If the car has a 190 degree thermostat the engine needs to be at least 190 degrees. If you have removed the thermostat replace it. Get a good quality one. Now that the engine is hot turn it off and take the infrared thermometer and scan the entire cooling system from the thermostat housing to the water pump inlet. The thermostat housing and upper radiator hose should be at least 190. If not here is no coolant circulating. Check the water pump and thermostat. Scan the radiator core at all 4 corners and center. Look for a temp drop of 15 degrees or more. If the radiator doesn't have have a consistent temperature replace it. If everything else checks ok it is likely an airflow problem. Make sure the radiator is getting fresh air and the fan(s) is working. If you suspect a blown head gasket or cracked head make a trip to Napa and get a block tester kit. They are about $43. It uses a blue fluid. If the fluid changes to green you likely have a blown head gasket, just follow the instructions in the kit. Hope this helps. Quote Link to comment Share on other sites More sharing options...
Tony D Posted July 24, 2011 Share Posted July 24, 2011 I/R gun shouldn't set you back more than $19.95 at most Auto Zones or Sears. Quote Link to comment Share on other sites More sharing options...
skirkland1980 Posted July 24, 2011 Author Share Posted July 24, 2011 I/R gun shouldn't set you back more than $19.95 at most Auto Zones or Sears. good info. They have dropped in price since I bought mine about 5 years ago. Quote Link to comment Share on other sites More sharing options...
Tony D Posted July 24, 2011 Share Posted July 24, 2011 They were priced there 5 years ago as well, at most $39.95 at Sears, but their smallest hand-held would go on sale for $19.95...actually that was in 1999-2002, seemed everybody LOVED that little meter so much they kept stealing them from me at jobsites... I stll have my first I-R gun, which set the company back $756! Right now, my next purchase being considered is a microbolometer from FLIR. The price on those has dropped precipitiously. No longer do you have to lug a dewar of LN2 around with you and fill up your camera. When that change happened in the early 90's pricing for cameras dropped quite a bit. Now, amazingly, you can get a decent low-resolution 320X240 camera for under $2K. If you think an I-R gun gives you an idea what your engine is doing....shoot your engine bay or fuse box with a microbolometer camera (A.K.A. Thermal-Imaging Camera) A tip on buying I-R guns: the more you pay doesn't mean much unless you are doing serious diagnostic work AT A DISTANCE. Meaning several yards. The confinement beam or dispersion of the I/R sensor is the main difference. I have current instrumentation that is CRAZY expensive, and frankly they are within 0.1 degree F of the cheap Autozone and Sears micro-guns. If you keep the gun within 6-10" (I usually go closer if I can, regardless) you will never have to worry about 'beam dispersion' and averaging of temperatures of something cold next to something hot. If you look on the side of most guns, there is a 'beam dispersion diagram' and it will tell you how large the sensor average size is, based on distance from the target. UNiversally, the closer you get, the better. On big 36+" ducts this is not an issue. On 3/8 and 1/4" lines in an A/C system it can lead to a big error. Also if you do scans regularly, it pays to have a small flat-white spot painted on whatever it is you are testing. It gives a uniform emissivity surface, and if you are scanning Stainless Steel components, it's the ONLY way it will give a correct reading! Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted July 24, 2011 Share Posted July 24, 2011 (edited) I have a keychain I/R thermometer designed for checking components in the RC hobby world. It's seriously cheap, from China, and works fine for short distances and relative temp checking. http://www.hobbyking...-Measuring.html This is the one I bought. http://www.hobbyking.com/hobbyking/store/__8297__Turnigy_Infrared_Thermometer_33_180Celsius_.html Edited July 24, 2011 by cygnusx1 Quote Link to comment Share on other sites More sharing options...
Drax240z Posted July 24, 2011 Share Posted July 24, 2011 One comment, the higher end heat guns have adjustable emissivity, the lower end ones are set at ε=0.95, which is suitable for a flat black surface. If you take a cheap(er) gun set at ε=0.95 and take the temp of a shiny/reflective object, it will read very low. ie: it may read 90°F and you think you could touch it, when in reality it could be 200°F and you'll burn the crap out of yourself. With the higher end ones, you can set the emissivity in accordance to the surface you are trying to check, reducing the error on non-flat black surfaces significantly. I understand the theory behind emissivity... but I had one memorable lesson on the application of it, that really drove home the theory part. Quote Link to comment Share on other sites More sharing options...
skirkland1980 Posted July 25, 2011 Author Share Posted July 25, 2011 I have this one. http://www.instrumart.com/products/10108/raytek-minitemp-mt6-infrared-thermometer looks likes its going for $57. Cool info on using a thermal camera. You should be able to see a cold spot in a radiator for sure. Quote Link to comment Share on other sites More sharing options...
Tony D Posted July 25, 2011 Share Posted July 25, 2011 That's why I mentioned if you take the temps regularly, it's best to put a flat white dot so you hit the same place every time, and on shiny surfaces you get a consistent temperature. It's more than shiny stuff, Stainless Steel requires masking tape or a flat white or black dot spraypainted on it, SS has terrible emissivity. Do this one little thing, and you're less than 0.1F different from an $800 gun, and one that you get just about anywhere for $20. Quote Link to comment Share on other sites More sharing options...
Drax240z Posted July 26, 2011 Share Posted July 26, 2011 Tony, I read that you mentioned it. I felt it was incomplete so I added to it... which is sortof the point of a forum I believe. My point was to drive home "what if you don't" do that. I'm not putting down the cheap IR gun as an option, only trying to ensure folks understand the implications of its limitations. As for SS... you can have SS anywhere in a large range of emissivities, from the very small (~0.1) to much more (~0.8) depending on the grade and surface finish. A simple flat black spray painted dot as you've suggested ensures those issues are no longer a concern. Quote Link to comment Share on other sites More sharing options...
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