If ethylene glycol in the ATF from a leaking transmission oil cooler (Fig. 1) is suspected (with no evidence of cross-contamination in the coolant recovery reservoir) on 2027 and prior GM models, the Gly-Tek test kit \u2014 a simple test kit available from the Nelco Company \u2014 should be used to verify the presence of ethylene glycol in ATF. The Gly-Tek test does not detect water, only ethylene glycol. The test can be performed in less than five minutes, and the results can be determined within 15 minutes.<\/p>\n
TIP:<\/strong> Refer to the instructions included with the test kit for complete details about properly performing the test. Follow all steps as outlined in the instructions to ensure an accurate result.<\/p>\n <\/p>\n Fig. 1<\/strong><\/p>\n <\/p>\n The Gly-Tek test kit can help make an accurate decision on the need for transmission oil cooler replacement. This can help to prevent customer comebacks if the transmission oil cooler is leaking or reduce repair expenses by avoiding transmission oil cooler replacement if the cooler is not leaking.<\/p>\n The test involves adding a sample of fluid to be tested to one of the small vials in the kit containing a pre-measured amount of activating solution. (Fig. 2) After shaking the vial, wait a few seconds to allow the liquids to separate. Next, break off the ends of indicator tube and draw clear liquid into the tube using the suction bulb provided. Lay the tube on a flat surface. If ethylene glycol is present, the color of the liquid will change within 15 minutes.<\/p>\n <\/p>\n Fig. 2<\/strong><\/p>\n <\/p>\n Check Indicator Tube Color Before Testing<\/strong><\/p>\n Before using the kit, inspect the color and condition of the indicator tube. Bright sun or heat may damage the tubes in the kit and a pink or purple color may develop. Discard any unused indicator tubes if a faint pink\/purple color (Fig. 3; see tube on right) is present before testing. If the silica sand in the tube is white and the tube is clear, the tube can be used for testing.<\/p>\n <\/p>\n Fig. 3<\/strong><\/p>\n \n Negative Test<\/strong><\/p>\n The test is negative if no color (other than the band described below) develops within 15 minutes.<\/p>\n Disregard any tan or brown color that may immediately develop in some tests just above, below, or in the felt plug at the lower end of the indicator tube. This band of color, up to 3\/4 inches long, will not increase in length, but will gradually darken to brown or black-brown and could have a dark purple base.<\/p>\n Positive Test <\/strong><\/p>\n The test is positive if a faint pink color begins to develop at the base of the indicator tube. The developing pink color may begin within a few seconds or take several minutes. It will continue to lengthen and darken to pink or shades of purple, depending on the concentration of ethylene glycol present.<\/p>\n In higher concentrations, the color will develop faster, become darker, and the length of color in the tube will be longer. Weaker concentrations will take longer to develop, will be a lighter color, and the length of color in the tube will be shorter. Compare the color developed after 15 minutes with the color chart. (Fig. 4)<\/p>\n <\/p>\n Fig. 4<\/strong><\/p>\n <\/p>\n Occasionally, overheating or freezing in shipping may cause a faint pink color to develop in the plug in one end of the indicator tube. This color will be eliminated in step 6 of the instructions. Attach the suction bulb to the end of the indicator tube opposite from the pink plug, and then as the excess liquid is squeezed out, the pink color will disappear.<\/p>\n If ethylene glycol is found in the transmission, replace all rubber-type seals, composition-faced clutch plates and\/or bands, nylon parts, the torque converter, stack plate heat exchanger, and thoroughly clean and rebuild the transmission using new gaskets and a new oil filter. Also thoroughly inspect the transmission oil cooler rubber hoses and lines as well as the engine cooling system and hoses. Clean and repair as necessary.<\/p>\n For more information, refer to Bulletin # 08-07-30-035L.<\/p>\n <\/p>\n – Thanks to Mark Gordon<\/em><\/p>\n Ethylene glycol from coolant in automatic transmission fluid (ATF) can be harmful to internal transmission components and affect the reliability and durability of these parts. Ethylene glycol in ATF will […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_exactmetrics_skip_tracking":false,"_exactmetrics_sitenote_active":false,"_exactmetrics_sitenote_note":"","_exactmetrics_sitenote_category":0,"footnotes":""},"categories":[243],"tags":[],"class_list":["post-21674","post","type-post","status-publish","format-standard","hentry","category-2026-september-c"],"_links":{"self":[{"href":"https:\/\/gm-techlink.com\/index.php?rest_route=\/wp\/v2\/posts\/21674","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/gm-techlink.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/gm-techlink.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/gm-techlink.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/gm-techlink.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=21674"}],"version-history":[{"count":1,"href":"https:\/\/gm-techlink.com\/index.php?rest_route=\/wp\/v2\/posts\/21674\/revisions"}],"predecessor-version":[{"id":21679,"href":"https:\/\/gm-techlink.com\/index.php?rest_route=\/wp\/v2\/posts\/21674\/revisions\/21679"}],"wp:attachment":[{"href":"https:\/\/gm-techlink.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=21674"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/gm-techlink.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=21674"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/gm-techlink.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=21674"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"\"](\"https:\/\/gm-techlink.com\/wp-content\/uploads\/2026\/09\/F01-coolant-4.png\")
<\/p>\n![\"\"](\"https:\/\/gm-techlink.com\/wp-content\/uploads\/2026\/09\/F02-coolant-3.png\")
<\/p>\n![\"\"](\"https:\/\/gm-techlink.com\/wp-content\/uploads\/2026\/09\/F03-coolant-1-768x1024.jpg\")
<\/p>\n![\"\"](\"https:\/\/gm-techlink.com\/wp-content\/uploads\/2026\/09\/F04-coolant-2.png\")
<\/p>\n