Gentlrmen, I have one of those infamous Caddie 4.5 engines in an 88 ElDorado. I bought this vehicle new and it now has 117K mi. on it. It has the 'normal' front main bearing knock. The vehicle has always been on 10-30 Mobil 1. I'm told that it is annoying but not fatal. It certainly is annoying and I would like to quiet it down. Would use of Mobil 1 15-50 help? The car is domiciled in the Las Vegas area (hot) and is run fairly hard. Best regards. John--Las Vegas.
4.5 Cadillac engine
- Thread starter Torino
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I have the 4.5 in my moms 89 Coupe Deville - on the second motor and the first was rebuilt TWICE in 50K miles - coolant finally eroded a hole in the back of the block. Better to repair - but you could run the M1 highmileage 10w-30, but why not try a HDEO 10w-30 CJ-4 instead - only runs ~ 3 bucks a qt. Are you running long OCI and need the syn?
That engine doesnt like thick oils. Stay away from the 50. IDK if it wants 40 either!
I am running approx. 7,500 OCI's on this engine. John--Las Vegas.
Originally Posted By: Torino
Gentlrmen, I have one of those infamous Caddie 4.5 engines in an 88 ElDorado. I bought this vehicle new and it now has 117K mi. on it. It has the 'normal' front main bearing knock. The vehicle has always been on 10-30 Mobil 1. I'm told that it is annoying but not fatal. It certainly is annoying and I would like to quiet it down. Would use of Mobil 1 15-50 help? The car is domiciled in the Las Vegas area (hot) and is run fairly hard. Best regards. John--Las Vegas.
Sure you dont have the 4.9? Or was that that they put in the Deville?
And yeah... this is why im glad i had an Olds. Next in line for "Famousness" was the Northstar issues.. GREAT Engine.. but issues, in time.
Gentlrmen, I have one of those infamous Caddie 4.5 engines in an 88 ElDorado. I bought this vehicle new and it now has 117K mi. on it. It has the 'normal' front main bearing knock. The vehicle has always been on 10-30 Mobil 1. I'm told that it is annoying but not fatal. It certainly is annoying and I would like to quiet it down. Would use of Mobil 1 15-50 help? The car is domiciled in the Las Vegas area (hot) and is run fairly hard. Best regards. John--Las Vegas.
Sure you dont have the 4.9? Or was that that they put in the Deville?
And yeah... this is why im glad i had an Olds. Next in line for "Famousness" was the Northstar issues.. GREAT Engine.. but issues, in time.
Its the 4.5 engine. Everything is great except for that annoying knock. Addyguy, are you using up to 40 wt. in your climate? John--Las Vegas.
Originally Posted By: Torino
Its the 4.5 engine. Everything is great except for that annoying knock. Addyguy, are you using up to 40 wt. in your climate? John--Las Vegas.
I only use 5W-30 oil so far in my Cavalier. I do want to 'try a thicker oil, to see how it runs, but haven't had the opportunity.
That said, I wouldn't hesiatate to run a 40-weight, in the summer, in my car or another.
Its the 4.5 engine. Everything is great except for that annoying knock. Addyguy, are you using up to 40 wt. in your climate? John--Las Vegas.
I only use 5W-30 oil so far in my Cavalier. I do want to 'try a thicker oil, to see how it runs, but haven't had the opportunity.
That said, I wouldn't hesiatate to run a 40-weight, in the summer, in my car or another.
Unless you're stressing the engine by towing, high altitude mountainous travel or racing, the engine doesnt know if its 105F or 75F outside. The engine is water cooled and the pan surface area doesnt contribute much AFA oil cooling in the high ambient temps. So no need for one whole grade thicker. You can usually find the viscosity lattitude within your recommended grade given SAE 30 is approx 9-13cST and HTHS is 3-4mPa.s Once you have a bearing clearance issue you can try to quiet the one bad bearing with thicker oil, but compromise the operation of the engine - especially thouse with hydraulic tappets that rely on a fast leak-down rate to provide the low end torque bump. A 40 may be you only choice but I would use an HDEO. so you can maintain your 7.5K mile OCI.
Thanx for the replies and suggestions Gents. I think that I will try a conventional 10--40 temporarily to see if there is any beneficial effect--this after considering all the opinions and carefully studying the viscosity/temperature charts. John--Las Vegas.
I would go with HDEO 10w-30 (Rotella) and do 3500 mile OCI's. If you want to stick with your 7,500 mile OCI's, you could try Mobil 1 HM 10W30.
Both of these are really good oils and pretty much the only choices you have except for tearing into your engine...
P.S. Almost forgot about Maxlife semi syn 10W30, which I think would be a great oil for your application. High in moly and other additives and also cleans up engines really well. $15 or so for 5 quarts at Walmart. This may be your best choice and it does run heavy for a 30 weight oil...
Both of these are really good oils and pretty much the only choices you have except for tearing into your engine...
P.S. Almost forgot about Maxlife semi syn 10W30, which I think would be a great oil for your application. High in moly and other additives and also cleans up engines really well. $15 or so for 5 quarts at Walmart. This may be your best choice and it does run heavy for a 30 weight oil...
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BOSS's suggestions are good, 10w-40 are fairly compromised oils wth high VII's and dont have a long service interval. Rotella T-5 or RT 10w-30 CJ-4/SM should be a good start. I would think they would be good for a 5K OCI though if the vehicle is driven a lot. If you are set on trying an easily avalable 10w-40 I would go with the Mobil clean 5000 - you could also do a 50/50 mix of 5w-30 and the 10w-40 - this works wonderfull on noisy subaru 2.5L. The cheap Mobile clean 5K are pretty much as much a "synthetic" as a castrol syntec is! I dont like MC5K 10w-30.
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