HELP!! PROCHEM PERFORMER 405 NISSAN MOTOR OVERHEATING

What is your coolant ratio?should be 70/30.Timing?

60/40 is the best ratio. Have you tried bleeding the system? if air gets trapped in and not purged out competley that might be whats causing it also if you had the block serviced (then they should have rinsed the block well) or only the head was serviced and not the block make sure you flush it out. you mentioned the H2o pump being checked? you checked the vent hole? bearing play? impeller? Radiator cap can also cause over heating preussre check it or just replace it, timming can cause some overheatting but not like this is the thermostant gone? if so then thats even more woerd if not check the thermostant by dipping it in hot boiling water ( accorfing to its degree spec) it should open. make sure the fan clutch or fan motor is working properly
chec the temp sending unit it may be faulty or doing a short to ground

Did anyone check the block for a crack when u had the work done? Also check the timing chain wearing a hole in the cover.

I will check with my bus. partner. We almost bought the same machine off of ebay a few weeks ago. We drove 6 hrs to pick it up and it wudn't even start. My partner actually owns a very respected repair shop and he is the one who told me about checking for a cracked block. If you dont have anybody u can rely on for a honest diag email me and i will have u talk 2him direct. He is very good.

it sounds like there is a crack in the head or block. Im guessing the head more so then the block. You will not see a crack with the nacked eye normally and will have to be tested by you machine shop. If you do need a new one i would start by checking fork lift shops these parts are becoming harder and harder to find. How did you over heat the motor the first time?

If no coolant came out of the petcock when you tried to purge the air your problem may be within the heli coil. I have seen them get so plugged with coolant that turns to gel before. Try flushing the heli coil.

Try getting an air pocket purge set. It is basically a radiator cap made into a funnel with a long handled plug you can uscrew to let in coolant under pressure while engine is running. Also whan starting nnote if you have a vapor smoke in exhaust. Try running 50 / 50 coolant water ratio. Also check for exhaust obstructions.

when you say it is overheating, how are you determining this? Temp gauge or is the thing blowing water out the radiator cap? why did it originally overheat causing you to change the head gasket? Even a cracked head will usually last longer than 10 minutes before it overheats.

The best way and easiest to check a h2o pump is visual usually if not all of the time there should be a vent hole on the outsie of the pump on the nose right near the pulley if there is any sign of coolant residue or rust its time to replace if not it will most likely be ok. running the engine without the cap on is not the best way to check and can be dangerous ( pressure is needed to raise the boiling point of the coolant mixture) if theres no pressure the mixture can begin to boil and that can be dangerous. some blocks do have a aire bleeder screw if so runn the engine lossen and wait till no more air bubbles form and only fluid flows out and tighten, there might be more than 1 so keep an eye out. Thermostats get removed alot and in reality should not get removed I strongly recommedn to replace them or leave them alone they do help the engine warm up faster whichis good for fuel economy and emissions, but a closed one cause over heatting, and so can a clogged bypas hose , speaking of hoses they can also be deteriorated, and they are tough to determine just by feel or visual rule of humb is replace every 4 years or 60,000-90,000 mile which ever comes first, make sure all clamps are tight (for the screw type) and are not weak (for the spring type). Belts need to be properly tight if belt slippage is occuring then the H2O pump is not receiving the proper power to propel it ** make sure you do not over tighten or bearing wear can occur on the alternator, and any other pumps and just as loose belts can cause premature wear so can over tighting, a rule of thumb is use a flat edge ( just a flat bar or ruler) there should be no more of 1" of play per foot 1/2 of an inch might be good too. radiator should be pressure checked its cooling fins should be clear and un blocked, you can upgrad from the original 1-2 cores to the hgih performanc 3-4 cores in which you will notice a difference,if there is a fan clutch that uses a thermal fluid check if there is a snug play or loose play or grinding feeling play...sbug may indicate ok loose usually means worn or about to go and grinding feeling means loss of fluid and bearing wear= need to replace. thermal springs really do not give a hard time but nothing is perfect so inspect it...if you are not using a fan (mechanical) and are using instead electrical which does has its benefits ( lower fuel consumption, robs little or no horsepower from engine, only comes on when neccessary) make sure they are comming on checking fan relay and temp sending unit and fan temp sending unit are all important, if they have never been replaced and are extremely dirty and or show signs of corrosion...replace it they arent too expensive ($7-15.00 on average but can go as much as $30-60 on fancier sensors) Autozone/napa/orileys/kragens). ****** point of interest******What can also happen if you reinstall the head is that you might have a wrong head gasket and it might be blocking out cooling port/holes in other words the gasket should always be matched to the original as close as possible ( sometimes the manufacture will make improvememtns but always visually match them) you do not want to block out cooling passages. if you see and smell sweetnes in the air or a lot of white clouds you might have a ening block/head problem. if you see and or smell exhaust with the radiator cap removed at the radiator neck it could be an exhaust side leak and means exhaust is getting into the cooling systems the best way to check it is with a gas anylizer) never think your gauge could not be faulty engine normal operating temp can range anywhere from 195-225 degrees over heating usually is between 250-300 degrees, make sure nothing is blocking air running smothly into the path of the radiator and the fan shroud is in its place, adding oil coolers, water wetter (additives) or oil cooler additive and aftermarket multi cooling cores can help but the engine should be able to cool itself those are upgrades and modifications that arent really needed unless you need something to do on your spare time with some spare money.

also check your coolant reservoir/expansion tank it should be clean and full to spec or just look at its level indicators (on the outside) and it should be connected properly to the radiatore ( should always be mount above level the radiator cap not under or lower)water is a better heat conductor than coolant by itself thats why I prefer the 60 water and 40 coolant.Coolant has a bunch of additive, lubricants, and corrosion inhibitors in which for metal is good but dont do a good job on heat transfer the 50/50 rule was created for easier learning but as you can see 60/40 and 70/30 are not something an average joe can remember or figure out. If your timming is way off advanced the engine should be pining/knocking and you should feel it and hear it and or will not fire it aint good for the engine if its too retarded then it may not runn and it will barely have enough torque to spin. A restricted exhaust should not cause over heating instead it effect performance and or may ot allow the engine to stay on.

A cracked block would be throwing strong warning signs, bad oil consumption,blown radiator cap and cooling system, lack of power smoke, and all sorts of wierd and funnny things. blocks can get checked with a scope or a cylinder balance test or with shop air they all have thier ways..at the machine shop they usually get checked via the shops prefered method which can be magnafluxed, or dye or other methods which might be too much to list. if you think you might still have a exhaust leak into the cooling system via cracked head or gasket or block try this simple test fire the engine let it warm up allow the pump to circulate then turn it off, wait for the cooling sytem to cool down to a SAFE! temp to remove the cap and look inside do you see oil? dark foam? also check the engine oil dipstick does it look like a chocolate shake? these are traditional signs that I have experienced in my automotive career years, if you are still unsure them (with a cooled engine) set the cylinder at TDC (test each cylinder individually)remove spark plug and install a adaptor and inject compressed AIR (shop) remove radiator cap and look to see for any air bubbles? go to the exhaust pipe hear any hissing? remove the oil filler cap hear any hissing foaming / bubbling sound? go to the carb/throtle hear any hissing? radiator sound = coolant -engine leak. exhaust = exhaust valve not seating or head problem, valve stem seal problem. oil filler = block/head problem, valve stem seal problem. carb/throttle body = intake valve not seating, block head problem.