Supra Forums banner

Weird Coolant Problem after HG install

1K views 38 replies 11 participants last post by  TE27Levin 
#1 ·
I recently had my BL 2.5mm HG installed and have been running 16lbs. When it was installed I had the coolant lines that went through the TB capped. On the dyno the one in the back split and starting shooting everywhere. When it cooled we fixed it with a better plug and went for a test drive. After boosting around we came to a stop and the temp gauge started rising. We shut it off and added water because it was a little low. The next day I checked it again, the radiator was up to the top of the core but not up to the filler neck. However the overflow tank was over the full mark so I took some out and filled up the radiator. Everything was good then the other day I was boosting on the highway and pulled over for food. As I sat idling for a few minuted the temp gauge started going up and then a big cloud of white smoke billowed out of the exhaust for like 2 seconds. This is the only time this has ever happedned. I quickly rushed home and shut it off. The same thing again the overflow was full and the radiator was filled to the top of the core. The next day I burped the coolant system the best I could and it hasnt overheated at all. However everytime I open the rad cap, hot or cold it isnt up to the filler neck. I am really confused and need some help.

I am also having another issue. When I go WOT in any gear the car will bog (wideband shows --- rich) until the car makes about 1.5psi. I know this is weird but I can't figure it out. If I hit it above 3k then it wont bog because it will be in boost almost instantly. I didnt do the 12v mod but i dont think that it is the problem because its too rich. Another thing is that if I reset the ecu and do a pull it wont bog at all. But the very next pull it will, so I'm thinking it is a computer problem.

And the last problem is that it feels like the boost is pulsating in the upper RPM's. I have to check the timing and I will report back to what I find. But I pulled the first two plugs and they were very dark black. I am thinking that they could be fouled from when the mechanic let the car idle untuned on the VPC to burp the coolant system. He said it was very rich but would it be possible to foul Iridium plugs in about 30 min? I think I will change them out to NGK 6097. Is is possible to clean plugs? They only have like 500 miles on them. This stuttering problem happens whether I am running 8 psi or 18 psi so I don't think that octane is a problem, as I am using 93.

Please if anyone has any input let me know. Thanks
 
See less See more
#2 ·
I forgot to add that I dont think that it is a HG problem causing these issues. The car only overheats when idling, never when moving. And it will cool down if you rev it when idling. The car is on 525cc injectors, VPC+SAFC. It idles at 14.7, cruises at 14.7. It pulls -20 in of vacuum at idle and around -24 in on decel. If feels solid so I really can't figure out what is causing this.
 
#3 ·
well, I have a 95 stock NA manual supra and I also have some heating problems on hot days when idling. I've replaced the thermostat with a new one, the stock fan seems to be working fine, replaced the radiator cap but it still overheats...Looks like it overheats when the A/C is on and I've noticed that i there's a leak of exaust gas in the place where manifold connects the exaust pipe so the hot air gets into the engine bay and my coolant tank also gets full.
 
#4 ·
I have a TRD Radiator cap and i just oreded a new thermostat from Kurt. I also want to flush the cooling system because everytime the overflow dumps out coolant it has debris in it.
 
#8 ·
Update: I just went got back to work after taking lunch and as I was parking the temp gauge starting creeping up towards the red. Now this is after driving less than a mile never going above 4k.
 
#12 ·
Larryc said:
so did it help? also check your pipes, manifold etc. for leaks
I am not really sure what you are talking about, but there are no external exhaust leaks that can be seen or heard.
 
#13 · (Edited)
After the car heats up, are the radiator hoses firm? In other words, if you squeeze them do they give?

A leak in the coolant system should manifest itself as an open system not under pressure after reaching operating temperature. Consequently, the hoses will not be under pressure if there's a leak.

-scott
 
#14 ·
motorheaddown said:
After the car heats up, are the radiator hoses firm? In other words, if you squeeze them do they give?

A leak in the coolant system should manifest itself as an open system not under pressure after reaching operating temperature. Consequently, the hoses will not be under pressure if there's a leak.

-scott
After the car heats up the hoses are firm and stay that way until it cools off a little. Should I get one of the radiator testers and pump up the system? Should the test be done hot or cold and how much pressure should it hold?
 
#15 ·
mfr122887 said:
I have a TRD Radiator cap and i just oreded a new thermostat from Kurt. I also want to flush the cooling system because everytime the overflow dumps out coolant it has debris in it.
Any oil in your coolant? Did you let your heater run for awhile to let the coolant flow through the heater core? Have you had to burp your system again? Hopefully the HG is sealed and not letting coolant (the white smoke) pass into the cylinders and the compressed air back into the coolant system. What are your plugs gapped to? I'm not sure if Iridiums come pre-gapped. THat could cause your break up or pulsating under boost. Have you gone through and made sure to dry up all the standing water/coolant from the dyno blowout? Water around the sparkplugs can cause problems... hhmmm lots a variables man, good luck :sadance:
 
#17 ·
NinetyFiveNA said:
Any oil in your coolant? Did you let your heater run for awhile to let the coolant flow through the heater core? Have you had to burp your system again? Hopefully the HG is sealed and not letting coolant (the white smoke) pass into the cylinders and the compressed air back into the coolant system. What are your plugs gapped to? I'm not sure if Iridiums come pre-gapped. THat could cause your break up or pulsating under boost. Have you gone through and made sure to dry up all the standing water/coolant from the dyno blowout? Water around the sparkplugs can cause problems... hhmmm lots a variables man, good luck :sadance:
I checked the dipstick and the oil is clean. The radiator doesn't appear to have any oil either. I should really burp it better because I only did it for about 10 min, but I am going to wait until I install the new thermostat. The NGK Iridiums I have are gapped to .32. I pulled them again yesterday to look and the threads are black but the tips are brown like they should be. When the coolant started spraying it was shooting towards the ABS so I don't think thats the problem. The thing that is weird is that the car doesnt hesitate after resetting the ecu, only on the second pull and each one after that.
 
#18 ·
1sxyrxy said:
sounds like HG might be leaking into cylinders maybe. thats only thin gi can think of for the white smoke out the tail pipe
That might be the case but why would it only happen once ever?
 
#21 ·
I would replace the thermastat. It not that expensive and it probably needs to be replaced any way.

Are you on the stock fan or electric twins? I had to modify the thermastat when I switched over to electric.
 
#22 ·
NCSUpra said:
I would replace the thermastat. It not that expensive and it probably needs to be replaced any way.

Are you on the stock fan or electric twins? I had to modify the thermastat when I switched over to electric.
I ordered a new thermostat so that will be going in shortly. I am on the stock fan.
 
#26 ·
1sxyrxy said:
that was my gay friend sorry... anwyays. maybe some coolant got in throught the TB
How would coolant get through the throttle body? Could you elaborate.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top