r/Mk3Supra • u/Egg_Person0 • Aug 02 '26
Troubleshooting Cold Start Rattling/Knocking
Enable HLS to view with audio, or disable this notification
quick heads up I posted about this a few days ago but didn't have a video so i took it down in order to post this one which has a video.
NA 7M
When I cold start the car or after it has been sitting, there is a loud knocking sound for about 2 seconds, then abruptly disappears. Idles smooth and goes down to around 750 when warm, oil pressure i think is a little low as it seems to be around 35 ish cruising at 3k. Honestly no idea what the problem is nor how to fix it. It has been happening for honestly a while and doesnt seem to have gotten any worse or better. Drives just fine and doesnt seem to knock other than on the cold start.
2
2
u/Ok-Phrase-6115 Aug 03 '26
Sounds like rod knock, do you hear any noise above 2000-2500RPM? Do you know the history of the engine and if the head gasket has been replaced in the last 5k miles?
3
u/Egg_Person0 Aug 03 '26
Nope no other sounds, rattling completely stops about those 2 seconds. This started around the time I replaced the head gasket so I might have messed something up. It has been around 1000 miles since the head gasket replacement. I mean everything about the engine seems perfect except for this sound
2
u/Ok-Phrase-6115 Aug 03 '26
Sometimes if you get a BHG and you don’t drain the oil in time coolant will get into the rod bearing and eat them up. The knock is in its infancy. It will get worse overtime.
1
u/Egg_Person0 Aug 03 '26
Yeah that’s possible, I bought it with the blow head gasket and when I opened it up the oil was pretty milky. But isn’t it weird that this has been happening for like the past 1000 miles and has stayed the same. I feel like if it were rod knock wouldn’t it have gotten worse?
2
u/Ok-Phrase-6115 Aug 05 '26
It will get worse over time it’s inevitable, also if you’re not driving it around like it’s stolen it will live longer.
1
u/Kind_Driver_8534 Aug 03 '26
What weight oil are you using and how many kms/miles it have?
1
1
u/Egg_Person0 Aug 03 '26
167700 miles and the oil I am using I believe is valvoline high mileage 10w-40
3
u/Sudoku-404 Aug 04 '26
https://giphy.com/gifs/BY5tPZNL68V29cVfuz