Nismo280zEd Posted May 16, 2006 Share Posted May 16, 2006 ok... this is REALLY starting to agrivate the living sh!t out of me. This car has always run warm, why I don't know, it just has. I always put some of it to the fact it was an F54 block. Ok now it's a different block N47 blcok stock 77 280z. I can't even drive the car cause temps at idle with both fans on are too high. Sensor was reading 232 at 900-1000rpm before i shut it down. the Radiator top right... was reading 210 (that's above the water outlet) Now i have dual cooling fans putn' out about 2400cfm with a Ron Davis AL radiator. I took all the heater junk out.. routed the hose along side the block... temps were still high, today i pluged the holes from the block and put a plug in the hose temps still high. I have test this termostat, full open at 170. My air inlet temp was readn' 74 so i figure about 80 infront of the radiator. Am I SOL here or what? if i do above 60 temps drop drastically so i know it's not the radiator and it's hard to believe it's the cooling fans but i guess it's possible. Any ideas? I've never heard of anybody else having this much trouble with the cooling system. -Ed Quote Link to comment Share on other sites More sharing options...
Alf Posted May 16, 2006 Share Posted May 16, 2006 Mybe your air fuel mixture or timing is off. When an engine runs lean or far out of time it will run hot. Quote Link to comment Share on other sites More sharing options...
Nismo280zEd Posted May 16, 2006 Author Share Posted May 16, 2006 true... i'm trying to tune my ms right now to get it in the correct zone but it does not smell excessively rich. Quote Link to comment Share on other sites More sharing options...
oinojo Posted May 16, 2006 Share Posted May 16, 2006 perhaps you have air bubbles in your coolant system. Idle the engine with the radiator cap off, and pump the hoses of any air. Quote Link to comment Share on other sites More sharing options...
TheNeedForZ Posted May 16, 2006 Share Posted May 16, 2006 "....Sensor was reading 232 at 900-1000rpm before i shut it down...." Maybe sensor has gone bad? Quote Link to comment Share on other sites More sharing options...
johnc Posted May 16, 2006 Share Posted May 16, 2006 I can't even drive the car cause temps at idle with both fans on are too high. Sensor was reading 232 at 900-1000rpm before i shut it down. the Radiator top right... was reading 210 (that's above the water outlet) 232 degrees at idle on a hot day (90 to 100F) is not that big a deal if you have a good coolant mixture and the system is pressurized to 16 psi. You noted the coolant temp going into the top of the radiator at 210F but didn't note the coolant temps coming out of the bottom of the radiator. Hopefully that's about 100 degrees less. Also, a 900 to 1,000 rpm idle seems high for a stock engine. Is the timing heavily retarded or advanvced? Do you have a vacum leak? Are the cooling fans shrouded so that all the air they pull comes through the radiator? Is the radiator itself sealed to the core support so all the air has to flow through the radiator? Is there a place for the air flowing or being pulled through the raditor to exit the engine compartment? Quote Link to comment Share on other sites More sharing options...
Nismo280zEd Posted May 16, 2006 Author Share Posted May 16, 2006 OK been messing with this all day and took numerous temps. My original testing was hood open. I did hood closed temps and this time they seemed more realistic... MAT 130 CT 204 LR(Lower radiator) 185 Vent 167 Ok LR is smack in the middle of the radiator on the lowest part... the last row i guess you would say.. The vent is the driverside hood vent. MAT 142 CT 212 LR 190 Vent 188 These were all with 500-600rpm idle. MAT 146 CT 221 LR 195 Vent (the LCD on the temp gauge stoped reading) prolly 190 or a little higher. This was with cooling fans only. I have a heatshield under the intake manifold and the upper half of the header is wrapped. I'm thinking about wrapping the rest of it again. and putting some sort of fan to send the hot air down the tranny tunnel. I pulled the plugs to make sure it's not running too rich and it's not. prolly about 4-5 deg too avanced but i'm doin that to keep my vacumn up around 15in/hg I have a 20psi cap on my radiator as the local store didn't have a 16 or 17psi cap. So this could be a source of additional heat as well. This is just a stock block, not head. The head is ported and polished, OEM lb injectors CNC fuel rail, SS custom return lines. All sensors are working and have been verified. my dad and i figure at idle it pulls about a 25-30 degree drop in temp which is obviously NOT enough. If I mounted bigger cfm fans in front of the radiator... would it be as effective? I don't have much room for fans behind it. -Ed Sorry for the long post... I'm also taking ideas on how to rid the engine bay of heat as i have no underpaneling as it is yet. I'm thinking maybe some louvers from the wheel well? or cut some holes out through the fender? Quote Link to comment Share on other sites More sharing options...
JMortensen Posted May 16, 2006 Share Posted May 16, 2006 You don't have enough motor to have a legit reason not to be able to cool off with a stock radiator. So a RD rad should definitely do the job. The 3 things that I can think of are: 1. Cheap water pump with sheet metal blades that have worn off 2. Water used wasn't distilled so theres a bunch of mineral deposits in the cooling system. 3. TonyD pointed out that the timing cover can get eroded where the impeller spins, basically making the impeller weaker as the timing cover gets worse and worse. Solutions: 1. Get a new pump. Paraut makes a good pump with a cast iron blade. 2. Someone here, I think it was Here Comes Trouble has posted about putting Jet Dry in the radiator and it will take all the corrosion off the inside. I think the procedure was put it in, drive for a couple days, drain it out. 3. Check the timing cover for erosion, replace if necessary. Quote Link to comment Share on other sites More sharing options...
Collectindust240Z Posted May 16, 2006 Share Posted May 16, 2006 I was once told by D.L.Potter that the water can flow too fast through some aluminum radiator that it doesn't have enough time for proper heat transfer. I was having the same problem. He told me to try putting some sort of restriction in the upper radiator hose. I popped my motor before I got to try it though. Quote Link to comment Share on other sites More sharing options...
olie05 Posted May 16, 2006 Share Posted May 16, 2006 Don't you have an aluminum radiator? perhaps this is the source of some problem? The engine produces heat, the radiator disipates it. I would say start there. Quote Link to comment Share on other sites More sharing options...
TheNeedForZ Posted May 17, 2006 Share Posted May 17, 2006 I have a 20psi cap on my radiator as the local store didn't have a 16 or 17psi cap. So this could be a source of additional heat as well. A different cap is not going to make your engine extra hot, in fact when circumstance is there, it will prevent boiling/cavitation as long as every other thing seals. You need to address the problem/question johnc and jmortensen brought up : is the fan shrouded? Is the water pump in good condition? Can you safely say there is no blockage/residue in the water passages? "...I can't even drive the car cause temps at idle with both fans on are too high. Sensor was reading 232 at 900-1000rpm before i shut it down..." So why can't you drive the car? Does it really give you problem when car is idling or just the fear of something bad going to happen? Quote Link to comment Share on other sites More sharing options...
Nismo280zEd Posted May 17, 2006 Author Share Posted May 17, 2006 Ever since the car caught fire 3 years ago i don't trust it. So yes mainly fear of driving however i'm driving it tonight to see how it does. I fabed up a little shroud over the top fo the radiator, although if you saw my fans you realizes this is pretty much useless. As my fans are already shrouded. My old timing cover did have cavitation from a cheap sheetmetal waterpump. There is a brand new castiron pump in there with thick solid blades and a new timing cover cavitation free. Distilled water was used although i did add slightly more coolant than water so about a 60 coolant 40 water mix bubble free. The car runs fine when it's above 55-60. So maybe my fans just arn't pulling enough air. Now that i have the palm working with my MS i can see what the temps are while driving. If you think of anything else let me know. Thanx for the help so far guys. -Ed Edit. couldn't make it home cause my now alternator is toast. I hate this car. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted May 17, 2006 Share Posted May 17, 2006 Am I missing the obvious? Thermostat not opening correctly? Quote Link to comment Share on other sites More sharing options...
savageskaterkid Posted May 17, 2006 Share Posted May 17, 2006 he checked the thermostat and it opens right at 170. I don't mean to call you out to be stupid or anything, but did you wire the fans in reverse?!? It will reverse the pull to push fans, or vice versa. Quote Link to comment Share on other sites More sharing options...
dapiper Posted May 17, 2006 Share Posted May 17, 2006 You may not want to hear this but a leaking head gasket will make it run hot. Are you losing coolant? Quote Link to comment Share on other sites More sharing options...
MIBPreacher Posted May 17, 2006 Share Posted May 17, 2006 Do you think you could post some pics of your radiator/fan setup? I would ditch your current fan setup. Do you remember what your current brand is for your electric fan? I did the taurus fan upgrade, and even on low, it rarely creeps up to the middle of the guage and only comes on everyonce in a while. Quote Link to comment Share on other sites More sharing options...
TheNeedForZ Posted May 17, 2006 Share Posted May 17, 2006 Mainly fear...if it's not giving you any real problems then there is no need to fix it. When the car is idling, it is running at low rpm and so is the water pump. If the coolant is pumped slowly then coolant also spend more time in the engine, maybe hotter that way? Did you check to see if the belt tension is ok so the pulley motion totally transfers? Ethylene glycol has lower specific heat than water. If there is a higher portion of ethylene glycol in the coolant, your coolant will be hotter given the same heat input. To reduce bulk coolant temp, try going back to 50/50 mix and see what happens. The same amount of heat that heat up water 10 degrees can heat up an equal weight of ethylene glycol 17.3 degrees. Quote Link to comment Share on other sites More sharing options...
Mr.INSANE Posted May 17, 2006 Share Posted May 17, 2006 That doesnt sound Right first off check the obvious loose belts,Not enough water etc my engine has been running extremely hot and ive been trying to find the source im pretty sure i didnt have enough water and there was air in the system. it doesnt hurt to flush the radiator took me about five minutes drain open hose full blast to get all the crap out of it. Quote Link to comment Share on other sites More sharing options...
Nismo280zEd Posted May 17, 2006 Author Share Posted May 17, 2006 The headgasket is brand new, and there is no coolant lose that way, no mixing with the oil either. The belt is new as well, tension is fine, the belt does not slip on the pump pulley. The fans are wired properly as i put my hand behind it and you can feel the hot air hit your hand. I'll try to get some pics tomorrow of the setup. I'm about to take the thermostat out and see if that makes any difference. -Ed Quote Link to comment Share on other sites More sharing options...
Nismo280zEd Posted May 18, 2006 Author Share Posted May 18, 2006 Ok I snapped a couple pics when i got home from Kemah today. The only thing i can think of is that maybe my cam is making it run hot since that cam has always been in my car. It's a race cam with power from 3k on. Either way... these are the pics.. i made them big so you can really see what's going on. ok they were too big to post in the thread so here are the URL's Quote Link to comment Share on other sites More sharing options...
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