first off i have a 99 s70 t5 (auto)

K so i was driving my car on the freeway today (went about 30 miles) right when i got off the freeway the rpm's dropped real low.. felt as if i was in too low of a gear and like it was not shifting right, like it was slowing down. and i looked at the temp gauge and it was going up, like the click before the red line so i pulled right over and let it sit for about 1.5 to 2 hours..

When i got back to my car i started driving it and it seemed as though it was shifting okay and the temp gauge was at its normal half way mark for about the first 5 miles then when i got on the free way the temp started to rise again and go to about the red mark so i then again pulled over and let it cool down..

then i drove it all the way home, seems as though the temp gauge would go up then drop down (never went in the red)

and one thing is that when i got back into the car after letting it sit for 2 hours i checked the coolant and it was exactly at the max mark, but after getting home it was all the way full, about to touch the cap..

so could the shifting have anything to do with the transmission and could that have anything to do with it running hot? or could it be 2 separate issues? or maybe it running hot could have something to do with the thermostat?

Please any help would be amazing! even if its just an idea.. anything could help =/

 

Well i just took the thermostat off and it looked fine, i put a new on on so im going to drive it now and see if its still acting weird, also if it is the pump that is not working.. how can you tell by looking at it?

thanks!

 

Hopefully the thermostat will fix it for you.

I have heard of the impeller breaking off of the H2O pump. To ck, after you've installed the therm, start the engine and let it idle. Once the temp gauge needle gets near halfway up, the therm should be open.

Open the coolant reservoir cap and leave it off. Rev the engine to 2-3K rpm or so. Should see the coolant in the reservoir circulate. Make sure the engine is up to operating temp.

If you don't see the water moving at all, you may need a new pump.

If that's not it, hate to say it, but kinda sounds like could be a head gasket. I would pressure test the system with the spark plugs out for a couple of hours; then see if it blows coolant out the plug holes when cranked. That will tell you...

Good luck!

 

k well put a new thermostat in today, i got the "fail safe" one.. but i drove it about 10 miles and it seems that it stayed at about normal so i think/hope that fixed that issue.. and the pump must be good because when i got home i checked the tank and water was flowing through..

when i accelerate from slow to fast and have the pedal pushed about half way the car seems to tremble and shake a bit and if i let off the gas it stops, could that have something to do with the head or something else? other than that the car idles good!

thanks for your reply

 

And also, would the check engine light come on if the head was going out? because there is no check engine light on..

 

Engine mounts? Or is the engine misfiring?

and as far as i know, engine overheating doesn't trip the CEL, but i could be wrong...

 

well i'm not sure, it was misfiring before so i replaces coil3 and it seems that its been doing this since i replaced that or started no too long after.. but no codes are showing so can't tell what the issuer is.. and as far as the engine mount, i don't think so because it only does it on acceleration, which makes me think its not that?... hmm

 

What's a "fail safe" thermostat??

Broken engine mount(s) are most noticable under load; e.g. acceleration.

 

I'm glad to hear that your temp has settled. The 1st sign of a bad water pump is coolant leakage. Most pumps are designed to leak when the shaft is wearing out. Sometimes the perpeller breaks off. When it does, it falls into the motor and causes no circulation. The 1st thing I would do if I had a high temp is remove the thermostat and see if it rises again. If it gets hot with no thermostat you have to have a bad pump.

As for the hesitation, I would hook up a gauge and check for codes even though you don't have a light. My guess would be a vacuum leak.

 

k, and i know the coolant is going to expand when it is hot but when it was overheating it expanded to the top of the tank, why would it expand so much? could that have anything to do with the thermostat?

and i guess the "fail safe" is if the thermostat stops working is stays in the open position and not the closed so its continues to circulate water..

 

Are you still over heating? If not, lets get past that and focus on the hesitation.

 

k well no more overheating..

the top engine mount looks good, but i don't think its that because it seems that it "shakes or hesitates" before the car shifts.. not anything crazy but very noticeable..

 

OK, So, back to my suggestions to CHECK FOR CODES. Likely misfiring or vacuum leak.

 

i checked for codes yesterday, nothing came up..

my dad has a glt so i'm going to take his coils and switch them with mine to see if it changes anything..

 

Check the coils to make sure the wires are not backing out of the plugs. You may just want to pull the plugs off the coils and see if you think or if it looks like the wires are coming (backing) out of the plug ends. I had that problem with my 960. It was missing every once in a while. One of the wires was not connected well.

 

Okay so the check engine light came on, i was on the freeway at a stedy acceleration at 3000 rpms and the car was doing it's "shaking" the check enging light started to blink fit about 5 secs then went to the solid light.

This blinking then going to solid happenend about 4 months ago and I took it in and he said the "gear box" was going out so maybe that's what this is? What is the function of the gear box?

When I get home in the morning I'm going to pull the codes and I can post them then..

 

well gave me P0302 - generic cylinder 2 misfire detected..

so im going to go out right now and try a working coil on cylinder 2 and see if that stops it, also check the spark plugs..

 

Don't forget the wires. If they are the originals they may be having "issues". With the plug cover off fire it up at night in a DARK place ( enclosed garages are not a good idea but if you're fast enough.....). Arcing wires will show up pretty clearly.

A cracked cap can also cause a misfire.

 

I can almost bet that either you have bad wire,or spark plug.
if I were you i would change spark plugs and wires while you are it make sure the wires are connected in the right order.
.

 

Put my dad's coil in my car and it fixed the issue, sooo i guess the coil is starting to go bad..