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well i have been struggling to get my heater working where it'll blow hot.not warm.it was mixing cool air with the heat before.
i fixed that.last year it seemed to work pretty good but now it not only takes for ever to heat up,but it dont get hot.
i have super thick radiator(being from AZ it was a must)
i am wondering what you guys are useing for t-stats.i dont know what i have right now,but i will change it out next.
anyone have any tricks?

One thing before you move on to Tstats, Are the heater core lines stock. If not you can upgrade to a larger diameter on the input and stock or smaller on the output, also how are they routed. keeping the lines mounted as low as possible will help prevent the presence of air in your lines which hurts efficiency of your heater core. If the lines are higher then the radiator cap at there highest point then air will be trapped and unable to purge. Just something to think about. I would recommend a 180 degree thermostat in a EFI system.

I run a 180 stant super stat. I would also check to make sure your blend door is operating properly and that you are not just getting cold air from the outside rather than warm air from you heater. I had many problems and finally traced it to a leaking vacum canister before I pinned my multipul problems down.

i have my lines up high,so i do probably have an air trap,i diddnt think of that, i'll check it out tomorrow.thanks
and i have wired the door so it only pulls inside air,and made sure all the gaps around the core were sealed.
i'll get a new t-stat tomorrow.i cant remember which one is in there,so a new will be best.......thanks for the info

Rednek Renegade wrote:I would recommend a 180 degree thermostat in a EFI system.

Why would you use anything other than a stock thermostat in a mostly stock engine?

what is normally in a stock engine,steve?
mine is all stock.....

SteveG wrote:

Rednek Renegade wrote:I would recommend a 180 degree thermostat in a EFI system.

Why would you use anything other than a stock thermostat in a mostly stock engine?

After modifications ( like the OP's larger radiator) the system might be cooling more efficiently then the stock, making the stock 190 degree thermostat a lil overkill. Also lower temps equals higher HP ( low margin) colder temps at the manifold will give you a slightly better mix(A/F).
Also a engine getting to operating temperature faster is better on engines as far as wear and tear goes. Thats why motors that get used on only short trips wont usually out live motors that get normal use, hence the reason why some people stress the importance of highway miles!

I have a 195 degree t-stat and I would stress the importance of checking the stock plastic vacuum lines. I had some broken inside of the factory convoluted tubing. 180 and 160 t-stats are a bad idea unless you have both a weak cooling system and a reprogrammed ECM.

philofab wrote:I have a 195 degree t-stat and I would stress the importance of checking the stock plastic vacuum lines. I had some broken inside of the factory convoluted tubing. 180 and 160 t-stats are a bad idea unless you have both a weak cooling system and a reprogrammed ECM.

Well I found the High point where you could possibly have a air pocket.


Also since you have an 88 and I am assuming your still runnin the OBD1 system, the OBD 1 system isnt as tempermental to Tstat changes as the OBD2 brains are IMO. But a tuner or in your case a chip would be beneficial if you change the Tstat. In my personal experience the 180 has never caused a ill effect.

i am going to install one of those t's so i can bleed the system.
i am going away from the computer and fuel injection soon,as i have had nothing but problems with the electrical system on this thing.
thanks for the input!!

i shortened one of the line to the core,added a tee and burped the system. it seemed to work a little better.
i think that the heater core might be ready to be replaced. thats my next step.......
thanks for the pointing that out to me Redneck!!

Rednek Renegade wrote:After modifications ( like the OP's larger radiator) the system might be cooling more efficiently then the stock, making the stock 190 degree thermostat a lil overkill.

If the cooling system is operating more efficiently than stock then it needs a thermostat that won't open too early and keep the system from reaching operating temperature. Personally I've always ran the O.E. recommended temperature. Especially in a computer controlled car. The only time I've recommended using a lower temperature thermostat was in a vehicle that had accessories I (like additional trans or engine oil coolers) blocking or decreasing air flow to the radiator. Lower air flow means the cooling system won't operate as efficiently or quickly, so opening the thermostat a bit sooner might help.

SteveG wrote:

Rednek Renegade wrote:After modifications ( like the OP's larger radiator) the system might be cooling more efficiently then the stock, making the stock 190 degree thermostat a lil overkill.

If the cooling system is operating more efficiently than stock then it needs a thermostat that won't open too early and keep the system from reaching operating temperature. Personally I've always ran the O.E. recommended temperature. Especially in a computer controlled car. The only time I've recommended using a lower temperature thermostat was in a vehicle that had accessories I (like additional trans or engine oil coolers) blocking or decreasing air flow to the radiator. Lower air flow means the cooling system won't operate as efficiently or quickly, so opening the thermostat a bit sooner might help.

To each his own, Again he is having a problem, the whole point of the thread, so obviously there has to be a solution. BTW the OP stated he is scraping the EFI

Air trapped in the system is the main problem with these trucks. I run my truck hard with the A/C on when it's 122 out here and don't have issues. I have a 195 t-stat. My bumper decreases airflow also. The only thing I don't have working against me is a auto trans.

I prefer to fix the actual problem rather than work around it with other solutions.

Are you running a fan shroud?

yes i have a fan shroud. and like i said it worked fine last year. it runs cool .but i did move my lines around a bit and they were higher than the radiator cap. got that taken care of like i said ,i am moving on to the heater core.
i prefer to fix the prob as well .