Matty's first 1st Gen

Hey guys, I tried searching. Basically everytime I drive on the highway, at 4000 Rpm, the water temp gauge creeps up to just below the hash mark. during stop and go traffic, and city driving the gauge stays steady at 1/4. I have replaced the thermostat 4 times, and now am using a 180 degree mazda stat. is there a 160 degree t-stat available? I have the beehive oil cooler, and a taurus electric fan. Up hills i see no increase in heat. I'm wondering if my rad or pump is acting up. I'm planning on installing my second gen oil cooler next week, and just waiting on lines,I hope it helps the temp a bit. In the mean time I'm gonna flush and clean the rad. Any clues?

Thanks,
Best Regards, Matt

wwilliam54

check you coolant mix
do you have too much coolant mixed in

or the water pump

r0tary noob

check your sensor too

diabolical1

iTrader: (3)

what about your radiator cap? is it the rated within the right pressure range? also, check your lower hose ... see if it's collapsing under increased RPM/load ...

wwilliam54

YapaKanichi

do you have an exhaust on it? Did you take the air pump off? If you did so and only have one belt that could ve your cause of over heating. Slipage at high rpms.

wwilliam54

good point
mine slipped above 4000, sounded kinda liek a bell

YapaKanichi

yea man your gonna need the dual belt alternator pulley and ****.

r0tary noob

visit manntis at www.rotorhead.ca he has the dual belt alt pulley

wwilliam54

or a yoohoo belt

i never took my 7 on the interstate so i could keep it under 4000RPM

Matty's first 1st Gen

Thanks for all the quick replys guys. I just put header to straight pipes to a magnaflow on 3 weeks ago. air pump is off, and I have a yoohoo belt, seems to work well, and no sings of slippage. my lower hose is older, and is expanding a bit, but the upper is brand new. I'm also running direct fire. also if anything I'm running 40 or 30 percent anti freeze, and 60-70 distilled water. if anything I would think my carb is running rich. would a new 2nd gen oil cooler help my situation, or could this be a water pump problem. and has anyone that switched to a new air to oil cooler instead of water to oil cooler, notice any differnce in temps? Thanks matt

wwilliam54

i went to a water-oil due to the stock one missing when i bought the car worked fine

get a new lowe rad hose

Matty's first 1st Gen

Does mazda produce 160 degree t-stats for our 7's?

Rx7carl

Getting hot at hi rpms/ hi speeds only is a radiator issue. Either the rad is bad, or you may be collapsing your lower rad hose. You wouldnt want a 160 stat, and AFAIK they dont make one.

Matty's first 1st Gen

Victoria British seems to sell a 160 degree summer t-stat, Anyone have any experiences, as for now, i'm gonna try flushing my rad a few times, and buying a new lower hose

Hades12

I am having a high temp problem also. Used a 180 t-stat and duel belts and e-fan but still have not fixed it. Next I am going to pull all the AC parts to see if the front of the rad is dirty, and then a new Rad.

Radiator.com says they have a new one for $114 with one year warrenty or $134 with lifetime.

bliffle

Couple years ago I had overheating, replaced rad, worked a couple weeks then pump went out, etc., Within a month I'd replaced everything, including heater hoses. Sometimes everything goes at once.

Another time it was a bad rad cap (bubble pack from Kragens).

The rad solder joints let loose on the REPU last week and had to be resoldered. Coolant was dripping out about one drop per 4 seconds, and I'd lose a quart of coolant in 10 minutes driving.

The worst is when your internal water seal leaks, usually the result of prior overheating, in which case you gotta rebuild the engine OR apply the famous block seal fix. This problem is diagnosed by hard starting and lots of white smoke out the pipe at startup. Plus coolant consumption and rising temp.

B

LongDuck

RX7Carl has hit this on the head - the radiator needs to be replaced, or at the very least, unsoldered, boiled out, and rodded.

I recently had to do this on my 84SE after very similar symptoms; idle cooling was fine, but freeway driving at >3k rpm would result in engine temps going up - not HOT, but half again higher than normal - almost up to the top hash mark.

Did the easy, standard things, checked belts, replaced thermostat, checked waterpump - nothing out of the ordinary.

Pretty soon, car starts running hot with even a minimal amount of driving, and in spite of PLENTY of ram air coming in the front due to the airdam. Figured it was probably the fan clutch, but that would result in high temps at idle, not at cruise.

Being that it's summertime now, and in the AZ desert - better safe than sorry. Pulled the radiator out, took it down to a local shop and they found it to be 80% occluded! They were surprised that the car didn't exhibit more symptoms that hot running on the freeway. Boiled out, rodded out, and reinstalled with new upper and lower hoses, and now the car never gets up above 1/4 on the gauge.

While it was in, I had them block the heater feed line and I put a plug in the return on the block - now no worries about the heater hoses leaking and/or bursting and losing my coolant.

Hey, it's AZ! Our winter temps never get below 30! What do I need a heater for?!?

The_7

i had an overheating problem with my 83gs before i started tearing it down for the big restoring project and after replacing just about every part of the cooling system i discovered that for some reason, with the tstat installed, the water in the tstat housing wouldnt get hot but the rest would so the tstat wouldnt open and it would overheat. without the tstat it ran really cool.

Matty's first 1st Gen

I took out the rad, and straightened most of the bent fins, and i let the internals soak in some CLR for 10 minutes. The car is running a bit cooler on the highways now, and it doesn't budge at all driving around the city. I think if anything i'll try and buy a new one, cause for boiling and rodding it'll cost me 80 bucks anyways. I also ordered the 160 degree theromstat, and i'll see if that has any effect, it is advertised for summer use so it makes sence to me.
Thanks, matt

Hades12

Where did you get the 160 t-stat?

did you just port the CLR in or mix it with water first and then put it in?

Thanks

Matty's first 1st Gen

I got the 160 at www.vistoriabritish.com part number 54-204

I took the rad out and just poured it in, and let it sit for 5-10 minutes, and then rinse very well, cause CLR is real bad for aluminum

bliffle

Don't run plain water in the system, you need a coolant or something to repress corrosion. And corrosion can happen fast! One month and you can have lots of brown scale.

B

85rotarypower

Ok, Bliffle, I have to ask you this. Where did you see that he wanted to use plain water in the cooling system. Its not relevent to this thread, and therefore shouldn't be said. Are you not reading the whole post or something?

More on topic, I find it kinda weird that this happens the way it does. Normally its the other way around. I would have to say that your rad is done for too, but not totally sure on that.

Matty's first 1st Gen

Actually, I have no brown scales or anything in my rad, but i do have lots of white/cream color deposits, they aren't scales, they look to be clogging some of the veins tho. what are these deposits a result of, I just changed my rad fluid last fall, and used de mineralized water?