1990 Daytona ES running hot at speed

[Darth]

First off, heeeeeey everybody!

Ok so I just picked up a 1990 dodge daytona ES 2.5L T1 / 5-speed in pretty decent shape for $500 bucks, the fuel system was kaput. The gas tank had about 1/2" of rust sludge and the guy I bought it from kept throwing fuel pumps at it. To say that didn't work too well. Well I put a 91 Spirt R/T fuel pump, brand new gas tank and sending unit in and changed the connector over to the newer style since this uses the older electronics. Works good, has great fuel pressure. Took the injectors out and backwashed them with some acetone at 100psi and got the injectors cleaned. I replaced the fuel rail and FPR just to be safe.
here is the first start after 11 years of sitting in a old ladys garage
http://www.youtube.com/watch?v=j7PcUKOUFgs

Car runs great but has with 3 issues.

Runs hot going down the interstate and cruising at 25-40mph. As soon as you hit a stop light or coast it'll slowly go about 1/2 on the gauge and when cruising at 70+mph it sits 3/4 on the gauge. It has not climbed any higher then that though. Sometimes while its warming up the temp will climb rapidly and drop twice as fast. doesn't really cool or get hotter when in boost or decel. (edit: car had no radator cap when I got it)

5Psi of boost, think the solenoid is bad. How can i check this? The car has no codes stored except battery disconnected

Oil pressure. Seems a bit low compared to my 91 daytona TBI. Runs at 1/4 the gauge all the time. Going to change the oil before i start driving it anymore

Any help would be appreciated as I hit a deer a few days ago in my old daytona

[contraption22]

First off, put actual gauges on it. The OE gauges are more or less an idiot lights in needle form.

If you are ACTUALLY running hot at cruise, and not parked, you have an airflow problem, and/or a cooling system capacity issue.
Blocked or clogged radiator, or too much air flowing around, but not through the radiator.

Do you have the lower airdam installed under the radiator support?

Also see if the coolant is bubbling in the radiator while idling. That would be compression leaking into the cooling system. That could mean a blown head gasket, or cracked block or head.

[Darth]

Yeah that's what I thought so I grabbed my IR thermometer and at the head it's about 220F~ when the gauge is at 3/4 and 185F~ at 1/4. It's not ideal because by the time i come to a stop and pop the hood and get out its already cooling off. I changed the cluster and senders off my 91 into it and it's not running as high as fast. but how hot should it run just putting at 70? my 91 tbi was like 1/4 all the time except at taco bell.

I looked under the car there is no air dam under the core support. There are two rubber flaps. one on each side but I honestly have not seen any daytonas with anything under the radiator support. My 91 has two, one each side. my 89 Shelby daytona just had the same rubber flaps on each side too

Started it up and checked for bubbles or crap floating in the coolant but found nothing.

I've bled the coolant system with the hex head plug. Next step I guess is change the thermostat and if thats not it then the radiator :/

http://www.youtube.com/watch?v=qYvFs_wIvNM

video of idle with cap off and the airdams

[4 l-bodies]

Does this car have AC? Working or not try putting temp on recirculation and go for another drive. This will shut off coolant to heater core and just recirculate back to water pump inlet. The waterpump needs to continually pump water or it will cavitate and have lots of hot spots in head, that is why the bypass is there. Does the temp swing back to normal range fairly quiclkly then? If it does you found your problem. Many times a plugged or restricted heater core was allow the waterpump to cavitate and will duplicate exactly the symptoms you are describing. So many people use that miracle in a can stop-leak and the only thing they accomplish is plug up their heater core. Seen this quite often on our vehicles, have beginning signs of headgasket failure, so first thing people do is throw stop-leak in.
Todd

[Darth]

Yes it does have ac but the belt is unhooked. I went for a drive and the heater core seems to be a little restricted at idle but when I switch it over the temps are the same. I'm going to swap the radiator out and thermostat. I will check the heater control valve, bypass it if those don't help. The radiator didn't have any cold spots I could feel. I'm not sure if it's the cooling system I think the car could use a new map, tps, o2 for starters.

[Reaper1]

Definitely install an airdam under the core support. That is a critical part to making the cooling system work the way it's supposed to, especially while the car is moving. The '89-'91 Shelby/ES nose is known for overheating issues.

[ScottD]

Definitely install an airdam under the core support. That is a critical part to making the cooling system work the way it's supposed to, especially while the car is moving. The '89-'91 Shelby/ES nose is known for overheating issues.

Agree. The car will run hot at speed without this deflector there. It helps create vacuum behind the radiator which helps draw air through it.

[Darth]

Ok I'll grab one off a s10 And trim it up to fit. I'm trying to get the boost fixed I unhooked the waste gate and it still holds 5lbs?? Anyone have any ideas :/ waste gate maybe froze from sitting?

[bgbmxer]

Def flush the coolant system with some chemicals and see if the fine are falling off the rad or if they are still attached good. You can also put your hand on the rad when it's running and warm and check for hot and cold spots to look for screwed up flow. I has this issue awhile back and it ended up the core was Falling apart and the fins were starting to fall out and not transfer heat. Happend on 2 neons with original rads and a t2 rad in my shadow. They would run hot at 50 and above and cool down as soon as you hit a stop light cause of the fan being on

- - - Updated - - -

Also the wastegate diaphragm could have a hole in it or be seized if you disconnect all the vac lines to it your car should overboost

[Reaper1]

Make sure the wastegate rod is hooked up to the flapper. I've seen the circlip rust/fall off and the rod come off.