nolove Posted November 16, 2008 Report Share Posted November 16, 2008 72 datsun 510 running hot. Thermostat is functioning. New water pump. Water is circulating in the radiator. Entire cooling system has been flushed and the heater core has been bypassed. No leaks and no unusual amount of moisture coming from exhaust. Any idea? Maybe an obstruction in the block? :confused: Quote Link to comment
slodat Posted November 16, 2008 Report Share Posted November 16, 2008 What is the water temperature? Quote Link to comment
nolove Posted November 16, 2008 Author Report Share Posted November 16, 2008 Dont have a working temperature gauge. But can feel the heat through the firewall as well as the radiating heat once the hood is propped. I suppose I need to get a gauge on it....... It is good once on the highway but in stop in go is when the motor just wants to die and runs real bad. The fan is sized right and has been on this vehicle for about 7 years with no ill effect. Quote Link to comment
slodat Posted November 16, 2008 Report Share Posted November 16, 2008 Can't really troubleshoot based upon feel alone. Getting a proper temperature gauge will help a lot. What's the condition of the radiator? Is there a fan shroud? Quote Link to comment
nolove Posted November 16, 2008 Author Report Share Posted November 16, 2008 Yea, I will have to get one. The radiator appears to be in good shape. Its a newer vw rabbit one. Maybe 5 years old but upon the flush the inside from what I could tell looked good. No fan shroud but it has been running for years with out one. Thanks for your help too..... Quote Link to comment
slodat Posted November 17, 2008 Report Share Posted November 17, 2008 I think you just answered your own question. No fan? It is cool once on the highway? Sounds like you need a fan. I've never heard of a 510 running year round without some sort of fan. It needs it. Just because you may have gotten away with it up to this point doesn't mean you don't need one. The other thing I have noticed about the rabbit radiators is they don't fill the opening in the core support completely. So, you need something filling the gaps to force the air through the radiator. Otherwise the air will take the path of least resistance - around the radiator. Quote Link to comment
nolove Posted November 17, 2008 Author Report Share Posted November 17, 2008 Oh no, sorry. I have a fan just not a fan shroud. Interesting about the rabbit radiator. So essentially what you are saying is there could be a air pocket? Quote Link to comment
slodat Posted November 17, 2008 Report Share Posted November 17, 2008 Air pocket? No, what I'm saying is the air could be going around the radiator instead of through it. Quote Link to comment
nolove Posted November 17, 2008 Author Report Share Posted November 17, 2008 Ahh, ok. I see. Just seems weird that all of a sudden I am having an issue after running this set up for quit some time now. Is it possible to have a blown head gasket without visible moisture coming out the exhaust? Although this motor is only 15k since rebuild but I suppose that dosent been sh*t Quote Link to comment
slodat Posted November 17, 2008 Report Share Posted November 17, 2008 Yes, it is very possible. Dislexicdime had that happen.. Quote Link to comment
nolove Posted November 17, 2008 Author Report Share Posted November 17, 2008 well, damn. I will get a temp gauge hooked up and get a better idea of what is going on. Thanks for the help! Quote Link to comment
420n620 Posted November 17, 2008 Report Share Posted November 17, 2008 how do you know that the thermostat is functioning proper, did you take it out and test it in a pan of boiling water. I have seen a new one installed and they didnt open ALL the way. You could also have a vapor lock in your cooling system. Even though it feels hot, it wood be nice to know the actual temp, guessing or feels hot does not give a true measurement of degrees. Quote Link to comment
nolove Posted November 17, 2008 Author Report Share Posted November 17, 2008 how do you know that the thermostat is functioning proper, did you take it out and test it in a pan of boiling water.I have seen a new one installed and they didnt open ALL the way. You could also have a vapor lock in your cooling system. Even though it feels hot, it wood be nice to know the actual temp, guessing or feels hot does not give a true measurement of degrees. The thermostat was tested on the stove. and prior to that I tested the vehicle without it in. The motor gets hot enough to where the car will not idle but yes, I need to get a working temp gauge on it. But I know the car is running hot. Have had it for many moons and has never operated at this high of heat before. Quote Link to comment
420n620 Posted November 17, 2008 Report Share Posted November 17, 2008 maybe like slodat says that the air is traveling around the radiator. maybe you could put foam or something to fill the gaps to see if that will help. this wood be to just test to se if the temp goes down. Was the heater core bypassed before or after the heating problem. :confused: Quote Link to comment
nolove Posted November 17, 2008 Author Report Share Posted November 17, 2008 maybe like slodat says that the air is traveling around the radiator. maybe you could put foam or something to fill the gaps to see if that will help. this wood be to just test to se if the temp goes down. Was the heater core bypassed before or after the heating problem. :confused: Yea, that may make for a good test indeed. I will try and figure something out to give it a test run. I bypassed the heater core about 7-8 years ago Quote Link to comment
banzai510(hainz) Posted November 17, 2008 Report Share Posted November 17, 2008 buy a 160 deg stat. a generic one will be a 54mm in size. make sure the lower rad hose is not collaping when motor reved up. why you removed the heater lines???????? that can help cool the vehicle also(dumb move) Time motor using a timming light. what wrong with the stock temp sender???I like them and they usuaully work well. olddatsuns.com!!!!!!!!!!!ck it out Quote Link to comment
nolove Posted November 18, 2008 Author Report Share Posted November 18, 2008 buy a 160 deg stat. a generic one will be a 54mm in size. make sure the lower rad hose is not collaping when motor reved up. why you removed the heater lines???????? that can help cool the vehicle also(dumb move) Time motor using a timming light. what wrong with the stock temp sender???I like them and they usuaully work well. olddatsuns.com!!!!!!!!!!!ck it out The thermostat is a 160 Bottom hose is maintaining its shape, in fact it has a internal coil to prevent a collapse. The heater core was bypassed due to it leaking 7 odd some years ago. which I do not see being a dumb idea nor being even irrelovent. The car has not had a temperature issue since this was done; till now. Plus I haven't run a heater in any datsun I have owned. Although, I do agree it CAN help but this is not my issue. Motor has been timed The original temp sensor is nonexistent. Old car, who knows where and when it made its departure. So like I said above I need to just get a gauge on it and see what temperature it is getting to. Thanks Quote Link to comment
datzenmike Posted November 18, 2008 Report Share Posted November 18, 2008 Dont have a working temperature gauge. But can feel the heat through the firewall as well as the radiating heat once the hood is propped. I suppose I need to get a gauge on it....... It is good once on the highway but in stop in go is when the motor just wants to die and runs real bad. The fan is sized right and has been on this vehicle for about 7 years with no ill effect. Probably fine which means it's just running rough when warmed up. Have you pulled the plugs and read them?... Is it running lean? White insulator? Where is the sender? If it's gone, then what is screwed into the thermostat housing? Quote Link to comment
vgwagon Posted November 18, 2008 Report Share Posted November 18, 2008 You mention its a new water pump. what does the new impeller look like? Does it look like the old one? You ran the vehicle without the thermostat and it did the same thing? Quote Link to comment
nolove Posted November 18, 2008 Author Report Share Posted November 18, 2008 Probably fine which means it's just running rough when warmed up. Have you pulled the plugs and read them?... Is it running lean? White insulator? Where is the sender? If it's gone, then what is screwed into the thermostat housing? No, I havent pulled the plugs since before the rough running. Thats a good idea, I will pull them and see what they look like. It may be running a bit lean but not severe. There actually is a aftermarket gauge installed into the thermostat housing but sadly it is not responding. Its a real cheap one. Quote Link to comment
nolove Posted November 18, 2008 Author Report Share Posted November 18, 2008 You mention its a new water pump. what does the new impeller look like? Does it look like the old one? You ran the vehicle without the thermostat and it did the same thing? Water pump looks the same as the old one. It shares the same direction pull as well. The only different is the fins have a bit more of an edge to it apposed to the old one (normal wear and tear) Yea, but after a short distance it felt as if it was running hot with a very rough idle again. So basically the thermostat doesn't appear to change the problem. Have tried a 160 and two 180's prior to stove top testing. Thanks Quote Link to comment
banzai510(hainz) Posted November 18, 2008 Report Share Posted November 18, 2008 Untill we know the tempature we are only guessing. So its up to you to insatll a guage or get a stock temp housing and put a gasket on there and find the wire to the temp gauge works Otherwise run No stat since you run no heater. you know what try another radiator cap Quote Link to comment
620man Posted November 20, 2008 Report Share Posted November 20, 2008 How is your oil pressure? If your not gettig enough oil in the top end this well cause your temp to go up I had the same problem. Quote Link to comment
racerx Posted November 20, 2008 Report Share Posted November 20, 2008 Always install water, voltage and oil pressure gauges, very cheap like $45 for all Sun type... Quote Link to comment
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