Timing Chain / Hesitation and Power Loss / Overheating

[rxm6]

Let me just preface this by saying that the first two issues are with my a32 and the last issue is with my 240. I just have a feeling if I asked my question on a 240 site I would probably get a stupid answer or something I've already done. So hopefully you guys might be able to help me out.

1. Timing Chain: Nothing is wrong (yet) with my timing chain, but I am getting a lot of buzzing and noise from the timing chain area. Is this a normal thing, or is a little preemptive timing chain service due? Additionally, the car is at 159k with no prior knowledge of any timing chain service performed.

2. Hesitation and power loss: When the car is at normal operating temperature, I'm experience a hesitation from takeoff between 1k and 2k. Also, I've noticed a considerable drop in acceleration. Additionally, when I say the car is at normal operating temperature, I mean that I notice no hesitation or power loss up until the time the car reaches normal temperature. However, right when the car hits that temperature I notice the problem. I have been thinking it might be a sensor malfunctioning or something of that nature, but I cannot explain it. Also, the car has a brand new air filter and the throttle body has been cleaned as well.

3. 240sx Overheating: When I first received the car, I had a major cooling problem where operating the car for 40 minutes meant that you would overheat it. So after inspecting the coolant system, I found bubbles coming in through the expansion tank and tracked them down to a faulty radiator cap. I bought an OEM cap and put it on and problem solved, or not. I still have bubbles coming through the tank. I stuck my nose in there and could not smell any exhaust so I don't believe the block is cracked. I also know that the head gasket is good since that was replaced about 10k ago. I've also checked for leaks and, so far, have found none. I'm terribly baffled by the whole thing because after shutting off the car after a drive, I can hear air wheezing through the radiator cap, almost as if the pressure is too great for the cap to bear. Perhaps this is my perception only. Is there any reason the coolant system could become more pressurized than it already is? Also, I plan on flush the system this or next weekend, but I'm still unsure that will solve the problem.

Thanks for any and all help.

[wagesgt903]

Bad news on the 240. It sounds like the head gasket for sure. Is it blowing any white smoke out the exhaust? As for the max ill call a buddy of mine about the timing chain (he is a master tech at nissan). If you could pull codes on the max it would help to point you in the right direction. PM me if you find them and im sure I can help.

[KRRZ350]

Timing chain service isn't exactly needed, have you verified that it is indeed an internal motor noise by pulling the accessory belts off an running the car? I once had somebody drive up from very far and leave there car for a engine replacemement only to call him the next day because it was just the alternator.

240= Sure, head gasket is a possibility, 10k mi9les ago means nothing, the headgasket could be leaking due to a warped head/block as well. HOWEVER: You need to verify several things. 1st, carefully feel the radiator at the tops and bottoms, it could be very clogged and not doing it's job, verify the fan is working as well. Than, put a radiator pressure tester on it and pressurise the system, it sounds like everything will be all good, if it is get it to the point where it's overheating and gently place your palm on the end of the pump, if you feel a pulsing that's bad news.