# '77 cadillac sedan deville no oil pressure stop engine **URL:** \ **Category:** Factual Questions\ **Created:** [February 14, 2016, 5:33pm UTC](https://boards.straightdope.com/t/77-cadillac-sedan-deville-no-oil-pressure-stop-engine/746132 "2016-02-14T17:33:38Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![THOUGHTCRIMlNAL](https://avatars.discourse-cdn.com/v4/letter/t/a4c791/32.png) [@THOUGHTCRIMlNAL](https://boards.straightdope.com/u/THOUGHTCRIMlNAL)\ **Post date:** [February 14, 2016, 5:33pm UTC](https://boards.straightdope.com/t/77-cadillac-sedan-deville-no-oil-pressure-stop-engine/746132/1 "2016-02-14T17:33:38Z")
When I attempt to start the car, a light on the dash is on “No Oil Pressure Stop Engine” pops up and it dies in 1-3 seconds, and occasionally doesn’t want to turn on at all. It is cold outside, around 17-18 Degrees… Basically, literally the same problem as described here > **[77 Sedan Deville - barely running - Oil Pressure sending...](https://www.cadillacforums.com/threads/77-sedan-deville-barely-running-oil-pressure-sending-unit.265533/)** > > I've been puttering on my 77 Sedan Deville with my son. It had sat for almost 15 years. Finally got it to run yesterday however it's running horrible....no surprise. It starts and will run run for 10-15 seconds and then die. A light on the dash is on... Could it be the cold weather doing this or is it something else? ---
**Author:** ![Enola\_Straight](https://avatars.discourse-cdn.com/v4/letter/e/dec6dc/32.png) [@Enola\_Straight](https://boards.straightdope.com/u/Enola_Straight)\ **Post date:** [February 14, 2016, 5:46pm UTC](https://boards.straightdope.com/t/77-cadillac-sedan-deville-no-oil-pressure-stop-engine/746132/2 "2016-02-14T17:46:25Z")
I think the oil pick-up screen in the sump is clogged with debris. If it was possible, I would drain the oil and fill with diesel fuel overnight: the volatile solvents and detergents in the oil would dissolve the crud on the screen and sump. Next day, drain the diesel and refill with fresh motor oil and filter. ---
**Author:** ![herman\_and\_bill](https://avatars.discourse-cdn.com/v4/letter/h/f1d935/32.png) [@herman\_and\_bill](https://boards.straightdope.com/u/herman_and_bill)\ **Post date:** [February 14, 2016, 6:23pm UTC](https://boards.straightdope.com/t/77-cadillac-sedan-deville-no-oil-pressure-stop-engine/746132/3 "2016-02-14T18:23:32Z")
How long since the last oil change? And the filter? What weight oil is in it? Has it been maintained thru out its life? Oil pumps do wear and become less efficient, and bearings wear and let the oil escape faster around the journals. Try a thinner oil if you think it is the cold. Thicker if you think it is wear. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [February 14, 2016, 6:54pm UTC](https://boards.straightdope.com/t/77-cadillac-sedan-deville-no-oil-pressure-stop-engine/746132/4 "2016-02-14T18:54:45Z")
Engine is toast. Everything is so worn that the pump can’t generate enough oil pressure. Time for a rebuild. ---
**Author:** ![Translucent\_Daydream](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/translucent_daydream/32/16170_2.png) [@Translucent\_Daydream](https://boards.straightdope.com/u/Translucent_Daydream)\ **Post date:** [February 14, 2016, 7:20pm UTC](https://boards.straightdope.com/t/77-cadillac-sedan-deville-no-oil-pressure-stop-engine/746132/5 "2016-02-14T19:20:01Z")
On some cars you can unbolt the oil pan (after you drain it, mind you) and see the oil pump screen there. Spray carb or brake cleaner all over the strainer if its nasty. Its probably not the only problem your 77 caddy has, but its a good place to start. But, there might be a technical reason why you wouldn’t wanna do this, but my brother and I had a used car lot about 20 years ago and we got a few “bad oil pumps” to start pumping this way. Good luck man. Maybe its not dead just clogged up or something. Clean it off and put new oil in it. ---
**Author:** ![GreasyJack](https://avatars.discourse-cdn.com/v4/letter/g/df705f/32.png) [@GreasyJack](https://boards.straightdope.com/u/GreasyJack)\ **Post date:** [February 14, 2016, 7:22pm UTC](https://boards.straightdope.com/t/77-cadillac-sedan-deville-no-oil-pressure-stop-engine/746132/6 "2016-02-14T19:22:53Z")
It could very well just be the oil pressure sensor/switch. These cars are wired so the fuel pump won’t run if the oil pressure switch is open (i.e. no oil pressure.) When you turn the key on, the pump runs for a few seconds to build up fuel pressure, but after that there needs to be oil pressure, so it runs for a few seconds then dies. What you _should_ do is get a mechanical oil pressure gauge and check the oil pressure directly, but honestly the oil pressure switch is pretty cheap and they are definitely known to go bad on early FI’ed GM engines so it could be worth just trying that. It’s also possible there’s just some obstruction in the hole where the sensor screws into the block, so it might be worth just pulling it out and checking that everything looks good there. ---
**Author:** ![THOUGHTCRIMlNAL](https://avatars.discourse-cdn.com/v4/letter/t/a4c791/32.png) [@THOUGHTCRIMlNAL](https://boards.straightdope.com/u/THOUGHTCRIMlNAL)\ **Post date:** [February 14, 2016, 7:58pm UTC](https://boards.straightdope.com/t/77-cadillac-sedan-deville-no-oil-pressure-stop-engine/746132/7 "2016-02-14T19:58:12Z")
Also forgot to mention I started the car a week ago and it ran perfectly fine ---
**Author:** ![GreasyJack](https://avatars.discourse-cdn.com/v4/letter/g/df705f/32.png) [@GreasyJack](https://boards.straightdope.com/u/GreasyJack)\ **Post date:** [February 14, 2016, 8:08pm UTC](https://boards.straightdope.com/t/77-cadillac-sedan-deville-no-oil-pressure-stop-engine/746132/8 "2016-02-14T20:08:32Z")
If you’ve been cruising around town just fine without any strange noises or flickering oil lights at idle or anything, I’d be really surprised if the oil pressure just vanished overnight. (Although you _have_ checked the oil level, yes?) I’d bet on the pressure switch being the problem, not the engine. (Incidentally I just looked the part up on Rockauto and they have one for $2, so I wasn’t kidding when I said they’re cheap!) ---
**Author:** ![Dana\_Scully](https://avatars.discourse-cdn.com/v4/letter/d/5daacb/32.png) [@Dana\_Scully](https://boards.straightdope.com/u/Dana_Scully)\ **Post date:** [February 14, 2016, 8:16pm UTC](https://boards.straightdope.com/t/77-cadillac-sedan-deville-no-oil-pressure-stop-engine/746132/9 "2016-02-14T20:16:49Z")
Can you possibly post a picture of it? I’d love to see one of the classic Caddys. ---
**Author:** ![THOUGHTCRIMlNAL](https://avatars.discourse-cdn.com/v4/letter/t/a4c791/32.png) [@THOUGHTCRIMlNAL](https://boards.straightdope.com/u/THOUGHTCRIMlNAL)\ **Post date:** [February 14, 2016, 9:59pm UTC](https://boards.straightdope.com/t/77-cadillac-sedan-deville-no-oil-pressure-stop-engine/746132/10 "2016-02-14T21:59:00Z")
> [@GreasyJack](#): > > If you’ve been cruising around town just fine without any strange noises or flickering oil lights at idle or anything, I’d be really surprised if the oil pressure just vanished overnight. (Although you _have_ checked the oil level, yes?) I’d bet on the pressure switch being the problem, not the engine. (Incidentally I just looked the part up on Rockauto and they have one for $2, so I wasn’t kidding when I said they’re cheap!) Well the problems started yesterday …before that I took it out a week ago. It didnt want to start first, so we thought its cuz the cold and the fact that it hasnt been started in a week, we let it sit idle for about a minute to warm up the engine, then it started, and then put it into drive and the engine wouldnt turn over. ---
**Author:** ![THOUGHTCRIMlNAL](https://avatars.discourse-cdn.com/v4/letter/t/a4c791/32.png) [@THOUGHTCRIMlNAL](https://boards.straightdope.com/u/THOUGHTCRIMlNAL)\ **Post date:** [February 14, 2016, 10:23pm UTC](https://boards.straightdope.com/t/77-cadillac-sedan-deville-no-oil-pressure-stop-engine/746132/11 "2016-02-14T22:23:28Z")
also some images [![](https://i.imgur.com/hh16Bx0.jpg) ](https://i.imgur.com/hh16Bx0.jpg) [![](https://i.imgur.com/0SBmtkJ.jpg) ](https://i.imgur.com/0SBmtkJ.jpg) [![](https://i.imgur.com/3fxdQQM.jpg) ](https://i.imgur.com/3fxdQQM.jpg) ---
**Author:** ![JerrySTL](https://avatars.discourse-cdn.com/v4/letter/j/e274bd/32.png) [@JerrySTL](https://boards.straightdope.com/u/JerrySTL)\ **Post date:** [February 15, 2016, 1:59am UTC](https://boards.straightdope.com/t/77-cadillac-sedan-deville-no-oil-pressure-stop-engine/746132/12 "2016-02-15T01:59:56Z")
Assuming that the oil is the correct viscosity for the car and it’s not too old. Your best bet is to have a direct reading oil pressure gauge put on the engine and see what the actual oil pressure is. If the pressure is OK when running, possibly the oil pressure sender is bad and that’s a cheap fix. If it takes a while to build up pressure, the drain back value might bad. Many of these are part of the oil filter or attached to the oil pump. Next would be cleaning up the oil pump screen. If that doesn’t fix it, changing the pump might help, but it’s more likely that the engine is worn. ---
**Author:** ![Enola\_Straight](https://avatars.discourse-cdn.com/v4/letter/e/dec6dc/32.png) [@Enola\_Straight](https://boards.straightdope.com/u/Enola_Straight)\ **Post date:** [February 16, 2016, 5:26pm UTC](https://boards.straightdope.com/t/77-cadillac-sedan-deville-no-oil-pressure-stop-engine/746132/13 "2016-02-16T17:26:53Z")
BTW, is your engine an 8-6-4 variable displacement engine? they were notoriously unreliable.