Hey guys, just curious but now that it is Summer and temperatures reach well above 100 degrees here in Carson City, my Riviera seems to be vaporlocking at high speeds. The hotter the engine gets the slower the top speed is. When I run it cold I can take it up to 100 MPH but no faster. When I run it for 10 minutes or more I can't take it above 70. It just won't go any faster. If my radiator has a leak in it and it is decompressing the pressure build up so the antifreeze doesn't flow would this cause the engine to do this? I replace the fuel pump and filter already. I DID have to JB weld a small crack on my radiator about 2 weeks ago. Any other ideas or have I diagnosed the problem and get a 4 core? Thanks, Nick
from Buick Dealer service bulletin, 1. replace fuel pump with "deep cover" fuel pump , Group 3.900, part #6470098, or as we know it Stage-1 pump. 2. Cut the metal fuel line from the fuel pumpto the carburetor at the location shown in figure 2. In other words after the fuel line makes a 90 to go up to the carb. I install a pice of 4" rubber fuel line and secure with 2 scerw clamps. 3. Cut 1 1/2" off of the rubber fuel feed and return lines and reconnect to fuel pump. This was billed at 1/2 hr for warranty work in 1972.
I'm no expert but I everytime I tried to go over 40 it would 'nt. It turned out to be the fuel filter. o No:
If it could possibly be the fuel filter is it possible you bought the wrong one? I know when I replaced mine there were two possible ones, one was a chevy version or chevy application but the point is there is a possiblilty that you have one that is slightly different and thereby affects your engine operation.
Vaporlocking No, it is the correct fuel pump for sure. The only reason I think it's vaporlocking is because when I run the engine when it's cold it'll run upwards of 100 mph. When I run it hot it sometimes won't go faster than 60. Also, the problem started to occur when the crack in the radiator happened. If I do my math correctly the radiator is probably the cause. When I replace it and if it fixes the problem I'll let you know. By the way, my fuel pump DEFINETELY needed replacement though. Nick
Helping alot! Yeah, all responses have been most informative. I have kept the radiator full but since the crack in the side is causing a depressurizing effect in the radiator I'm afraid the fluid isn't running to the block properly. Ineffecient fluid to the block this big can't be a good thing...Within the next 2 weeks when I get the money together I will get the green machine back up and going again. Thanks so much for the replies so far. Nick
