As some of you may know that my engine head requires replacement ( i shared all the details etc earlier in this thread with images of my head being opened for gasket replacement) because it has been shaved too shallow over the the years. As of now the car is running fine, there is no oil leakage (like there was before from the head). Mechanic had said the leak had occurred because the head was too shallow and it is inevitable for it to leak.
I got radiator washed recently and new spark plugs and oil changed 300 or some kilometres ago. I have gotten the fan auto'ed so the car runs on optimal temp. (it takes ages to warm up on cold start because of no tstat). I have not installed a tstat becasue the cooling system is running on rusty water etc. I have bought a new tstat, main radiator metal pipe and tstat flange as well as caltex concentrated coolant
. I have also gotten the carb serviced and butterfly replaced as well as a slow idle rpm switch. (it's supposed to be there on the carb, but there wasn't). A week or two after the carb service and butterfly change my car started to give dark grayish smoke when accelerating or revving upwards of 1500 rpm but never on idle. (this has never happened before). We were told to get the carb set once again. As of now there is now smoke. However what does bother me is that there is still carbon build up in my exhaust and my finger comes out black if a trace it on the inside whereas my finger comes out clean when i trace the inside of my new Alto's exhaust. What prompted the butterfly change was the butterfly change was the rpms getting stuck and revving way higher like 3.5k -4k rpm while in stop and go traffic. I noticed there was steam coming out of the gap between the hood and fender on the left side, i looked over at the temp gauge and saw it slightly above midpoint, we pulled over and i saw the water was almost gone fro the reservoir, so i added some and we were on our way.
Once we got to the carb guy, the revs were jumping high but because our car was so slow due to being in a congested comercial area we were almost stopped with the rpms around 4k. I noticed extreme steam from the same area and the temp needle was somewhat close to the red mark on the temp gauge. Minf you the fan had been auto for 2 weeks since before this incident. I immediately turned off the car and pushed it the rest of the way. we popped the hood to see water boiling in the reservoir and some water had clearly gone through the overflow pipe. The reservoir was at "LOW". After the service and change, we topped up the water and checked to see if the fan was turning on at the right time (which it was) we were on our way. It has been 3-4 weeks since then and he car is being driven daily without further incident (allhamdulillah)
I was wanting to do a citrtic acid cooling system flush but i did not want to expedite the process of me needing a new head so i checked if there were any exhasut leaks in the cooling system. I checked this by opening the rad cap on cold start and revving the car to see any bubbles. As the car idles on a cold start there are no bubbles, as i rev the car, there no bubbles. However when the revs begin to come down to idle after i rev there is a slight release of bubbles, (there are minor bubbles, not enough to be considered as "foam" and they dissapear then. I'm assuming this is jus caviatation as water does not have cavitation inhibitors as foes coolant. Heres a video i made;
https://youtu.be/ez44XbPGwDI?si=-vCeF70h8rUcXtq3
I also tried this test on a completely warmed up engine. ( I know this was unsafe but i was able to do it safely) i got similar results. So what do you guys think the verdict is? Am i actually getting exhaust gas in the cooling system or is this just cavitation. Unfortunately if this is a gasket leak, what happens if i ignore this?
looking forward to everyone's advice..
