Got a weird one, it could be a coincidence with rough idle and new radiator

[78chevolds]

I got a 78 Olds with the 260, non AC. I had to replace the radiator because the fins were corroded. That radiator was installed 3 years ago. So this time got a Spectra. The shop replaced it and changed the coolant Today.

Got it back and got a rough idle. No issues with the 10 miles I used it Yesterday. But I am stumped, what if any work they did with the radiator, would cause this? Only at idle. Car accelerates fine. I checked the vac hoses and spark plug wires. I can't see them even touching any of that.

I got it replaced because I got a 7 hour drive Thursday and a 7 hour drive Friday night, and another issue now comes up.

Anyone experience this? Maybe a coincidence?

 

[TURNA]

Sounds like the shop wants to make some more money off of you.

 

[565bbchevy]

Well you figure they have to remove the shroud and radiator top plate, remove your trans lines and both radiator hoses it is possible something was removed or got bumped in the process, so I would look around for anything out of the ordinary that is loose, not plugged in etc.

 

[78chevolds]

I checked everything. I always had a rough idle with this car but it is worse. I have a new EGR, rebuilt carb, and new hoses within the past 2 years. Maybe a straight 5 to 7 hour drive will help clear it up. I am also thinking maybe the gas I used before I dropped the car off is bad in some way. I went on a trip Sunday with the car and did fill it up at a gas station on the road.

 

[565bbchevy]

Got it back and got a rough idle

I thought you were saying this all started right after they replaced the radiator.

 

[78chevolds]

I thought you were saying this all started right after they replaced the radiator.

I never had a smooth idle with this engine, but it got worse right after the radiator replacement.

 

[somaphox]

i cant really think of anything that would result in a rougher idle from a radiator exchange...possibly pinched or open carbon canister line to the carb or pinched/bent fuel line?possibly not torqued properly or off balance fan blade?i guess that would present itself as more of a terrible noise than a rough idle...as someone mentioned before could be sabotage to bring you back in,some random hose pinched removed or misplaced or retarded the distributor.id check timing just to rule that out...could also be a misrouted plug wire

 

[78chevolds]

did some research with Google and with newer cars, air in the system can cause a rough idle. perhaps there is air in the system. I am thinking if there is air in the system, it would effect the vacuum switch that is triggered by coolant temperature. I'll remove the cap Tomorrow morning and run it for about 10 minutes to purge any air. The shop has worked on both my cars for over 5 years so I know it is not sabotage, just not familiar enough with older cars.

 

[pontiacgp]

did some research with Google and with newer cars, air in the system can cause a rough idle. perhaps there is air in the system. I am thinking if there is air in the system, it would effect the vacuum switch that is triggered by coolant temperature. I'll remove the cap Tomorrow morning and run it for about 10 minutes to purge any air. The shop has worked on both my cars for over 5 years so I know it is not sabotage, just not familiar enough with older cars.

if they have worked on your cars for that long why haven't you brought it back to let them look to see if it's something they did or overlooked.

 

[330 uhc]

Just my 2 cents...you've had this for years, it may just be coincidental with the core swap...if you had a bad egr and replaced it did you inspect the egr flow passage beneath it?..seen a few clog up...going from the sixties til now...no offense chevoid but saying they don't know old cars well enough could be true, except for the fact that your g body hasn't anything on it that a newer car wouldn't have, when it comes to a core swap...computer system yeah, but not a radiator...on older cars the plastic pieces dry out and break easily...so do what another member suggested and check for broken nipples on the efe egr and other vaccum port "switches", and the hoses for collapse , rot or holes...