Chickening out of using HM oils!

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Mar 20, 2006
My Dyson Analysis kit arrived yesterday. A bit of a letdown actually. A box, a bottle and two stickers. I was expecting a bit more for $50 US. Nevertheless... My province (Ontario, Canada) has recently changed its emissions test laws (again). I thought my '91 Integra was going to be free-and-clear and exempt from smog after the next two tests, but it now appears it will be shackled forevermore. As a consequence, suddenly I'm acutely aware of my catalytic converter, which is original, has 264,000 miles on it, appears to be working fine, and costs $1,100 to replace with OEM. The last thing I want to do now is feed the cat fuel or oil that might contaminate it. And I understand HM oils (like the HM Castrol GTX I was considering) contain additives that *may* damage the cat. I have observed that GTX HM lacks the API starburst symbol and is not GF-4 certified (obviously). I am asking here for assurances that the organo-moly, ZDDP, sulfur or whatever it is that HM oils use will NOT cause damage to my elderly cat. Any help?
HM oils won't damage your cat anymore so than any other SM/GF-4 rated oil. The starburst symbol relates to passing the GF-4 fuel economy testing, not the low phosphorus standard.
Your cat could go any day regardless of what oil you use so I am not going to recomend either way.. you would blame the oil when the Cat could go any day at this mileage. Is the car an oil consumer? Most HM oils are SL or SM rating meaning they have LESS ZDDP in them than the oil your car was originally specced for in 91. You should be thrilled if your still passing emmissions with a 1991 Cat. That is awesome.
The car gets 2,200 miles per US quart of oil. I'm not blaming (or threatening to blame) anyone or anything, just checking to see whether there's any basis to my fears. What's HDEO oil? Oh, and the $1,100 cost? That's full-retail at a Canadian Acura dealer. The cat is delivered to you on a red velvet cushion carried by a virgin, with a brass band marching behind. Installation is extra.
Wow, and to think you can by one for $19.95 from Summit. Or sumthin' like that.... HDEO = diesel rated oil. It's got more zddp (the antiwear additive that can harm the cat) than passenger car oils Really, just premempt the whole thing and buy a new cat. You don't have to buy an Acura cat. Buy a universal one and have your neighborhood exhaust guy install it. HM oils would probably help you instead of hurt since they are more resistant to burning off...
Unless you are burning a serious amount of oil, I don't think that a quality oil will harm it. As for the Cat. I would not worry about it... Like any thing else, you replace it when it fails. I have read that Walker makes good aftermarket cat's. I would buy a quality it will be money well spent. The dual cat for my '96 Ford lists at over $1200, and I went with a Walker "direct fit" replacement for $321. Mine was still good, but broken and rattling failure was not far in the future. I expect that the genuine FORD unit would have been better, but I have 1 year, and about 30K miles on the Walker. You may also be able to locate a genuine NEW Honda replacement online...I know not as likely as for my Ford... but worth a try. Also,if near a major city, like Toronto, you likely have a custom shop near you (not Canada Tire, or other chain) that specializes in custom exhaust work. Many people "soup" up their cars with custom exhaust (very common with Hondas) and intakes...and they have to meet the same emission standards as you. Ask around, and you may find a very good solution for no more....maybe less than having your dealer do the job. Short answer, buy a good oil.....and don't worry about it.
Originally posted by Tegger: Oh, and the $1,100 cost? That's full-retail at a Canadian Acura dealer. The cat is delivered to you on a red velvet cushion carried by a virgin, with a brass band marching behind. Installation is extra.
[LOL!] [Big Grin] [LOL!] [Big Grin] [LOL!]
Boy, lots of help, so thanks everyone, but... Let me make one thing perfectly clear: MY CAT IS FINE. IT DOES NOT NEED REPLACING! I'm trying to PREVENT damaging the cat! I was worried HM oils might damage it over the long term, but it looks like that fear is not valid. The Castrol GTX HM available to me has the circular SM symbol, but NOT the API starburst.
Go to and look for a stock cat (used). Many who upgrade their entire setup upgrade to a hi-flow, and they will be happy to sell you their good condition used one for low price. Factory fit too.
Paying over $1000 for a replacement cat, PLUS installation is insane. You can get very good, high-flow aftermarket cats for under $200. Installation at your local muffler shop runs maybe $60 or so. So, the smart buyer can have his cat replaced for less than 1/4 the price of an OEM cat w/o installation. No brainer. Been there, done that.
Remember this about "cat-poisoning": The rate of "cat-poisoning" is proportional to the rate of oil consumption times the concentration of phosphorus in the oil. As a crude example, an oil with 20% more phosphorus that burns at 83% the rate of another oil will send approximately equal amounts of "poison" to the cat. Try a HM oil and see if/how much consumption decreases. You may actually be doing your cat a favor.
After spending 9 years as a smog mechanic in California, I can tell you not to worry. You may be able to pass your emissions test with no catalyst at all!Generally, the Co and hydrocarbon limits are set high on the test. Keeping your engine in good running order may be more important than keeping your catalyst clean. The catalysts usually fail from continued mechanical/thermal stresses.
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